Merge pull request #1883 from devin-donnelly/release-1.5
Merge latest changes from Master into Release 1.5
This commit is contained in:
devin-donnelly
@@ -36,8 +36,8 @@ or be treated as an anonymous user.
|
||||
## Authentication strategies
|
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|
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Kubernetes uses client certificates, bearer tokens, an authenticating proxy, or HTTP basic auth to
|
||||
authenticate API requests through authentication plugins. As HTTP request are
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made to the API server plugins attempts to associate the following attributes
|
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authenticate API requests through authentication plugins. As HTTP requests are
|
||||
made to the API server, plugins attempt to associate the following attributes
|
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with the request:
|
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|
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* Username: a string which identifies the end user. Common values might be `kube-admin` or `jane@example.com`.
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+101
-95
@@ -11,44 +11,39 @@ assignees:
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## What is a node?
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`Node` is a worker machine in Kubernetes, previously known as `Minion`. Node
|
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A `node` is a worker machine in Kubernetes, previously known as a `minion`. A node
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may be a VM or physical machine, depending on the cluster. Each node has
|
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the services necessary to run [Pods](/docs/user-guide/pods) and is managed by the master
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components. The services on a node include docker, kubelet and network proxy. See
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the services necessary to run [pods](/docs/user-guide/pods) and is managed by the master
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components. The services on a node include Docker, kubelet and kube-proxy. See
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[The Kubernetes Node](https://github.com/kubernetes/kubernetes/blob/{{page.githubbranch}}/docs/design/architecture.md#the-kubernetes-node) section in the
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architecture design doc for more details.
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## Node Status
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Node status describes current status of a node. For now, there are the following
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pieces of information:
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A node's status is comprised of the following information.
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### Node Addresses
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### Addresses
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The usage of these fields varies depending on your cloud provider or bare metal configuration.
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* HostName: The hostname as reported by the node's kernel. Can be overridden via the kubelet `--hostname-override` parameter.
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* ExternalIP: Typically the IP address of the node that is externally routable (available from outside the cluster).
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* InternalIP: Typically the IP address of the node that is routable only within the cluster.
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* ExternalIP: Generally the IP address of the node that is externally routable (available from outside the cluster)
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### Phase
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* InternalIP: Generally the IP address of the node that is routable only within the cluster
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Deprecated: node phase is no longer used.
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### Node Phase
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Deprecated: Node Phase is no longer used
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### Node Condition
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### Condition
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The `conditions` field describes the status of all `Running` nodes.
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| Node Condition | Description |
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|----------------|-------------|
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| `OutOfDisk` | `True` if insufficient free space on the node for adding new pods, otherwise `False` |
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| `Ready` | `True` if the node is healthy ready to accept pods, `False` if the node is not healthy and is not accepting pods, and `Unknown` if the Node Controller has not heard from the node in the last 40 seconds |
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| `OutOfDisk` | `True` if there is insufficient free space on the node for adding new pods, otherwise `False` |
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| `Ready` | `True` if the node is healthy and ready to accept pods, `False` if the node is not healthy and is not accepting pods, and `Unknown` if the node controller has not heard from the node in the last 40 seconds |
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Node condition is represented as a JSON object. For example, the following response describes a healthy node:
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conditions mean the node is in sane state:
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The node condition is represented as a JSON object. For example, the following response describes a healthy node.
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```json
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"conditions": [
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@@ -63,25 +58,26 @@ If the Status of the Ready condition is "Unknown" or "False" for longer than the
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In versions of Kubernetes prior to 1.5, the node controller would [force delete](/docs/user-guide/pods/#force-deletion-of-pods) these unreachable pods from the apiserver. However, in 1.5 and higher, the node controller does not force delete pods until it is confirmed that they have stopped running in the cluster. One can see these pods which may be running on an unreachable node as being in the "Terminating" or "Unknown" states. In cases where Kubernetes cannot deduce from the underlying infrastructure if a node has permanently left a cluster, the cluster administrator may need to delete the node object by hand. Deleting the node object from Kubernetes causes all the Pod objects running on it to be deleted from the apiserver, freeing up their names.
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### Node Capacity
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### Capacity
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Describes the resources available on the node: CPUs, memory and the maximum
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Describes the resources available on the node: CPU, memory and the maximum
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number of pods that can be scheduled onto the node.
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### Node Info
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### Info
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General information about the node, for instance kernel version, Kubernetes version
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(kubelet version, kube-proxy version), docker version (if used), OS name.
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General information about the node, such as kernel version, Kubernetes version
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(kubelet and kube-proxy version), Docker version (if used), OS name.
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The information is gathered by Kubelet from the node.
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## Node Management
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## Management
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||||
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Unlike [Pods](/docs/user-guide/pods) and [Services](/docs/user-guide/services), a Node is not inherently
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created by Kubernetes: it is either taken from cloud providers like Google Compute Engine,
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or from your pool of physical or virtual machines. What this means is that when
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Kubernetes creates a node, it is really just creating an object that represents the node in its internal state.
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After creation, Kubernetes will check whether the node is valid or not.
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For example, if you try to create a node from the following content:
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Unlike [pods](/docs/user-guide/pods) and [services](/docs/user-guide/services),
|
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a node is not inherently created by Kubernetes: it is created externally by cloud
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providers like Google Compute Engine, or exists in your pool of physical or virtual
|
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machines. What this means is that when Kubernetes creates a node, it is really
|
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just creating an object that represents the node. After creation, Kubernetes
|
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will check whether the node is valid or not. For example, if you try to create
|
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a node from the following content:
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||||
```json
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{
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@@ -96,117 +92,127 @@ For example, if you try to create a node from the following content:
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||||
}
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```
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Kubernetes will create a Node object internally (the representation), and
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validate the node by health checking based on the `metadata.name` field: we
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assume `metadata.name` can be resolved. If the node is valid, i.e. all necessary
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services are running, it is eligible to run a Pod; otherwise, it will be
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ignored for any cluster activity, until it becomes valid. Note that Kubernetes
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will keep the object for the invalid node unless it is explicitly deleted by the client, and it will keep
|
||||
checking to see if it becomes valid.
|
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Kubernetes will create a node object internally (the representation), and
|
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validate the node by health checking based on the `metadata.name` field (we
|
||||
assume `metadata.name` can be resolved). If the node is valid, i.e. all necessary
|
||||
services are running, it is eligible to run a pod; otherwise, it will be
|
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ignored for any cluster activity until it becomes valid. Note that Kubernetes
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will keep the object for the invalid node unless it is explicitly deleted by
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the client, and it will keep checking to see if it becomes valid.
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Currently, there are three components that interact with the Kubernetes node interface: Node Controller, Kubelet, and kubectl.
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Currently, there are three components that interact with the Kubernetes node
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interface: node controller, kubelet, and kubectl.
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### Node Controller
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Node controller is a component in Kubernetes master which manages Node
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objects.
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The node controller is a Kubernetes master component which manages various
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aspects of nodes.
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||||
Node controller has mutliple roles in Node's life. First is assigning a CIDR block to
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||||
the Node when it is registered (if CIDR assignment is turned on). Second is keeping the
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||||
node controller's list of nodes up to date with the cloud provider's list of available
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||||
machines. When running in cloud environment whenever a node is unhealthy node controller
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||||
asks cloud provider if the VM for that node is still available. If not, the node
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||||
The node controller has multiple roles in a node's life. The first is assigning a
|
||||
CIDR block to the node when it is registered (if CIDR assignment is turned on).
|
||||
|
||||
The second is keeping the node controller's internal list of nodes up to date with
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||||
the cloud provider's list of available machines. When running in a cloud
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environment, whenever a node is unhealthy the node controller asks the cloud
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||||
provider if the VM for that node is still available. If not, the node
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||||
controller deletes the node from its list of nodes.
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||||
Third responsibiliy is monitoring Node's health. Node controller is responsible for updating
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||||
the NodeReady condition of NodeStatus to ConditionUnknown when a node becomes unreachable
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||||
(i.e. node controller stops receiving heartbeats e.g. due to the node being down), and then
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later evicting all the pods from the node (using graceful termination) if the node continues
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||||
to be unreachable (the current timeouts are 40s to start reporting ConditionUnknown and 5m
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||||
after that to start evicting pods). Node controller checks the state of each node every
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`--node-monitor-period` seconds.
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||||
The third is monitoring the nodes' health. The node controller is
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||||
responsible for updating the NodeReady condition of NodeStatus to
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||||
ConditionUnknown when a node becomes unreachable (i.e. the node controller stops
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||||
receiving heartbeats for some reason, e.g. due to the node being down), and then later evicting
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||||
all the pods from the node (using graceful termination) if the node continues
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||||
to be unreachable. (The default timeouts are 40s to start reporting
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||||
ConditionUnknown and 5m after that to start evicting pods.) The node controller
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||||
checks the state of each node every `--node-monitor-period` seconds.
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||||
|
||||
In 1.4 release we updated the logic of node controller to better handle cases when a
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big number of Nodes have problems with reaching the master machine (e.g. because
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||||
master machine has networking problem). Starting with 1.4 node controller will look at the
|
||||
state of all Nodes in the cluster when making a decision about pod eviction.
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In Kubernetes 1.4, we updated the logic of the node controller to better handle
|
||||
cases when a big number of nodes have problems with reaching the master
|
||||
(e.g. because the master has networking problem). Starting with 1.4, the node
|
||||
controller will look at the state of all nodes in the cluster when making a
|
||||
decision about pod eviction.
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||||
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||||
In most cases, node controller limits the eviction rate to `--node-eviction-rate` (default 0.1)
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per second, meaning it won't evict pods from more than 1 node per 10 seconds.
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In most cases, node controller limits the eviction rate to
|
||||
`--node-eviction-rate` (default 0.1) per second, meaning it won't evict pods
|
||||
from more than 1 node per 10 seconds.
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||||
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||||
The node eviction behavior changes when a node in a given availability zone becomes unhealthy,
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||||
node controller checks what percentage of nodes in the zone are unhealthy (NodeReady condition
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||||
is ConditionUnknown or ConditionFalse) at the same time. If the fraction of unhealthy nodes is
|
||||
at least `--unhealthy-zone-threshold` (default 0.55) then the eviction rate is reduced: if
|
||||
the cluster is small (i.e. has less than or equal to `--large-cluster-size-threshold`
|
||||
nodes - default 50) then evictions are stopped, otherwise the eviction rate is reduced to
|
||||
`--secondary-node-eviction-rate` (default 0.01) per second. The reason these policies are
|
||||
implemented per availability zone is because one availability zone might become partitioned
|
||||
from the master while the others remain connected. If your cluster does not span multiple cloud
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||||
provider availability zones, then there is only one availability zone, namely the whole cluster.
|
||||
The node eviction behavior changes when a node in a given availability zone
|
||||
becomes unhealthy. The node controller checks what percentage of nodes in the zone
|
||||
are unhealthy (NodeReady condition is ConditionUnknown or ConditionFalse) at
|
||||
the same time. If the fraction of unhealthy nodes is at least
|
||||
`--unhealthy-zone-threshold` (default 0.55) then the eviction rate is reduced:
|
||||
if the cluster is small (i.e. has less than or equal to
|
||||
`--large-cluster-size-threshold` nodes - default 50) then evictions are
|
||||
stopped, otherwise the eviction rate is reduced to
|
||||
`--secondary-node-eviction-rate` (default 0.01) per second. The reason these
|
||||
policies are implemented per availability zone is because one availability zone
|
||||
might become partitioned from the master while the others remain connected. If
|
||||
your cluster does not span multiple cloud provider availability zones, then
|
||||
there is only one availability zone (the whole cluster).
|
||||
|
||||
A key reason for spreading your nodes across availability zones is so that workload can be
|
||||
shifted to healthy zones when one entire zone goes down. To enable this behavior, if all
|
||||
nodes in a zone are unhealthy then node controller evicts at the normal rate `--node-eviction-rate`.
|
||||
The corner case for that is when all zones are completely unhealthy (i.e. there's no healthy node in
|
||||
the cluster). In such case node controller assumes that there's some problem with master machine
|
||||
connectivity and stops all evictions until any connectivity is restored.
|
||||
A key reason for spreading your nodes across availability zones is so that the
|
||||
workload can be shifted to healthy zones when one entire zone goes down.
|
||||
Therefore, if all nodes in a zone are unhealthy then node controller evicts at
|
||||
the normal rate `--node-eviction-rate`. The corner case is when all zones are
|
||||
completely unhealthy (i.e. there are no healthy nodes in the cluster). In such
|
||||
case, the node controller assumes that there's some problem with master
|
||||
connectivity and stops all evictions until some connectivity is restored.
|
||||
|
||||
### Self-Registration of Nodes
|
||||
|
||||
When kubelet flag `--register-node` is true (the default), the kubelet will attempt to
|
||||
When the kubelet flag `--register-node` is true (the default), the kubelet will attempt to
|
||||
register itself with the API server. This is the preferred pattern, used by most distros.
|
||||
|
||||
For self-registration, the kubelet is started with the following options:
|
||||
|
||||
- `--api-servers=` tells the kubelet the location of the apiserver.
|
||||
- `--kubeconfig` tells kubelet where to find credentials to authenticate itself to the apiserver.
|
||||
- `--cloud-provider=` tells the kubelet how to talk to a cloud provider to read metadata about itself.
|
||||
- `--register-node` tells the kubelet to create its own node resource.
|
||||
- `--api-servers=` - Location of the apiservers.
|
||||
- `--kubeconfig=` - Path to credentials to authenticate itself to the apiserver.
|
||||
- `--cloud-provider=` - How to talk to a cloud provider to read metadata about itself.
|
||||
- `--register-node` - Automatically register with the API server.
|
||||
|
||||
Currently, any kubelet is authorized to create/modify any node resource, but in practice it only creates/modifies
|
||||
its own. (In the future, we plan to limit authorization to only allow a kubelet to modify its own Node resource.)
|
||||
its own. (In the future, we plan to only allow a kubelet to modify its own node resource.)
|
||||
|
||||
#### Manual Node Administration
|
||||
|
||||
A cluster administrator can create and modify Node objects.
|
||||
A cluster administrator can create and modify node objects.
|
||||
|
||||
If the administrator wishes to create node objects manually, set kubelet flag
|
||||
If the administrator wishes to create node objects manually, set the kubelet flag
|
||||
`--register-node=false`.
|
||||
|
||||
The administrator can modify Node resources (regardless of the setting of `--register-node`).
|
||||
Modifications include setting labels on the Node, and marking it unschedulable.
|
||||
The administrator can modify node resources (regardless of the setting of `--register-node`).
|
||||
Modifications include setting labels on the node and marking it unschedulable.
|
||||
|
||||
Labels on nodes can be used in conjunction with node selectors on pods to control scheduling,
|
||||
e.g. to constrain a Pod to only be eligible to run on a subset of the nodes.
|
||||
e.g. to constrain a pod to only be eligible to run on a subset of the nodes.
|
||||
|
||||
Making a node unscheduleable will prevent new pods from being scheduled to that
|
||||
node, but will not affect any existing pods on the node. This is useful as a
|
||||
preparatory step before a node reboot, etc. For example, to mark a node
|
||||
Marking a node as unscheduleable will prevent new pods from being scheduled to that
|
||||
node, but will not affect any existing pods on the node. This is useful as a
|
||||
preparatory step before a node reboot, etc. For example, to mark a node
|
||||
unschedulable, run this command:
|
||||
|
||||
```shell
|
||||
kubectl patch nodes $NODENAME -p '{"spec": {"unschedulable": true}}'
|
||||
kubectl cordon $NODENAME
|
||||
```
|
||||
|
||||
Note that pods which are created by a daemonSet controller bypass the Kubernetes scheduler,
|
||||
and do not respect the unschedulable attribute on a node. The assumption is that daemons belong on
|
||||
and do not respect the unschedulable attribute on a node. The assumption is that daemons belong on
|
||||
the machine even if it is being drained of applications in preparation for a reboot.
|
||||
|
||||
### Node capacity
|
||||
|
||||
The capacity of the node (number of cpus and amount of memory) is part of the node resource.
|
||||
Normally, nodes register themselves and report their capacity when creating the node resource. If
|
||||
The capacity of the node (number of cpus and amount of memory) is part of the node object.
|
||||
Normally, nodes register themselves and report their capacity when creating the node object. If
|
||||
you are doing [manual node administration](#manual-node-administration), then you need to set node
|
||||
capacity when adding a node.
|
||||
|
||||
The Kubernetes scheduler ensures that there are enough resources for all the pods on a node. It
|
||||
checks that the sum of the limits of containers on the node is no greater than the node capacity. It
|
||||
includes all containers started by kubelet, but not containers started directly by docker, nor
|
||||
includes all containers started by the kubelet, but not containers started directly by Docker nor
|
||||
processes not in containers.
|
||||
|
||||
If you want to explicitly reserve resources for non-Pod processes, you can create a placeholder
|
||||
pod. Use the following template:
|
||||
If you want to explicitly reserve resources for non-pod processes, you can create a placeholder
|
||||
pod. Use the following template:
|
||||
|
||||
```yaml
|
||||
apiVersion: v1
|
||||
|
||||
@@ -27,7 +27,7 @@ a Kubernetes cluster from scratch.
|
||||
|
||||
### Local-machine Solutions
|
||||
|
||||
[Minikube](/docs/getting-started-guides/minikube/) is the recommended method for you to create a single node kubernetes cluster locally for purposes of development and testing. Setup is completely automated and doesn't require a cloud provider account.
|
||||
[Minikube](/docs/getting-started-guides/minikube/) is the recommended method for you to create a single node kubernetes cluster locally for purposes of development and testing. Setup is completely automated and doesn't require a cloud provider account.
|
||||
|
||||
Use the [Minikube getting started guide](/docs/getting-started-guides/minikube/) to try it out.
|
||||
|
||||
@@ -45,6 +45,8 @@ clusters.
|
||||
|
||||
[Platform9](https://platform9.com/products/kubernetes/) offers managed Kubernetes on-premises or any public cloud, and provides 24/7 health monitoring and alerting.
|
||||
|
||||
[OpenShift Dedicated](https://www.openshift.com/dedicated/) offers managed Kubernetes clusters powered by OpenShift and [OpenShift Online](https://www.openshift.com/features/) provides free hosted access for Kubernetes applications.
|
||||
|
||||
### Turn-key Cloud Solutions
|
||||
|
||||
These solutions allow you to create Kubernetes clusters on a range of Cloud IaaS providers with only a
|
||||
|
||||
+1
-1
@@ -340,7 +340,7 @@ We can now build and publish a new container image to the registry with an incre
|
||||
|
||||
```shell
|
||||
docker build -t gcr.io/$PROJECT_ID/hello-node:v2 .
|
||||
gcloud docker push gcr.io/$PROJECT_ID/hello-node:v2
|
||||
gcloud docker -- push gcr.io/$PROJECT_ID/hello-node:v2
|
||||
```
|
||||
|
||||
Building and pushing this updated image should be much quicker as we take full advantage of the Docker cache.
|
||||
|
||||
@@ -25,8 +25,7 @@ for database debugging.
|
||||
|
||||
1. Create a pod:
|
||||
|
||||
export REPO=https://raw.githubusercontent.com/kubernetes/kubernetes.github.io/master
|
||||
kubectl create -f $REPO/docs/tasks/access-application-cluster/redis-master.yaml
|
||||
kubectl create -f http://k8s.io/docs/tasks/access-application-cluster/redis-master.yaml
|
||||
|
||||
The output of a successful command verifies that the pod was created:
|
||||
|
||||
|
||||
@@ -59,8 +59,7 @@ a `disktype=ssd` label.
|
||||
1. Use the configuration file to create a pod that will get scheduled on your
|
||||
chosen node:
|
||||
|
||||
export REPO=https://raw.githubusercontent.com/kubernetes/kubernetes.github.io/master
|
||||
kubectl create -f $REPO/docs/tasks/administer-cluster/pod.yaml
|
||||
kubectl create -f http://k8s.io/docs/tasks/administer-cluster/pod.yaml
|
||||
|
||||
1. Verify that the pod is running on your chosen node:
|
||||
|
||||
|
||||
@@ -43,8 +43,7 @@ for the `Pod`:
|
||||
|
||||
1. Create a Pod based on the YAML configuration file:
|
||||
|
||||
export REPO=https://raw.githubusercontent.com/kubernetes/kubernetes.github.io/master
|
||||
kubectl create -f $REPO/docs/tasks/configure-pod-container/cpu-ram.yaml
|
||||
kubectl create -f http://k8s.io/docs/tasks/configure-pod-container/cpu-ram.yaml
|
||||
|
||||
1. Display information about the pod:
|
||||
|
||||
|
||||
@@ -39,8 +39,7 @@ file for the Pod defines a command and two arguments:
|
||||
|
||||
1. Create a Pod based on the YAML configuration file:
|
||||
|
||||
export REPO=https://raw.githubusercontent.com/kubernetes/kubernetes.github.io/master
|
||||
kubectl create -f $REPO/docs/tasks/configure-pod-container/commands.yaml
|
||||
kubectl create -f http://k8s.io/docs/tasks/configure-pod-container/commands.yaml
|
||||
|
||||
1. List the running Pods:
|
||||
|
||||
|
||||
@@ -33,8 +33,7 @@ Pod:
|
||||
|
||||
1. Create a Pod based on the YAML configuration file:
|
||||
|
||||
export REPO=https://raw.githubusercontent.com/kubernetes/kubernetes.github.io/master
|
||||
kubectl create -f $REPO/docs/tasks/configure-pod-container/envars.yaml
|
||||
kubectl create -f http://k8s.io/docs/tasks/configure-pod-container/envars.yaml
|
||||
|
||||
1. List the running Pods:
|
||||
|
||||
|
||||
@@ -32,12 +32,11 @@ In this exercise, you create a Pod that runs one container.
|
||||
The configuration file specifies a command that runs when
|
||||
the container starts.
|
||||
|
||||
{% include code.html language="yaml" file="termination.yaml" ghlink="/docs/tasks/debug-pod-container/termination.yaml" %}
|
||||
{% include code.html language="yaml" file="termination.yaml" ghlink="/docs/tasks/debug-application-cluster/termination.yaml" %}
|
||||
|
||||
1. Create a Pod based on the YAML configuration file:
|
||||
|
||||
export REPO=https://raw.githubusercontent.com/kubernetes/kubernetes.github.io/master
|
||||
kubectl create -f $REPO/docs/tasks/debug-pod-container/termination.yaml
|
||||
kubectl create -f http://k8s.io/docs/tasks/debug-application-cluster/termination.yaml
|
||||
|
||||
In the YAML file, in the `cmd` and `args` fields, you can see that the
|
||||
container sleeps for 10 seconds and then writes "Sleep expired" to
|
||||
@@ -70,7 +69,7 @@ the container starts.
|
||||
|
||||
1. Use a Go template to filter the output so that it includes
|
||||
only the termination message:
|
||||
|
||||
|
||||
```
|
||||
{% raw %} kubectl get pod termination-demo -o go-template="{{range .status.containerStatuses}}{{.lastState.terminated.message}}{{end}}"{% endraw %}
|
||||
```
|
||||
@@ -99,7 +98,7 @@ Set `terminationMessagePath` as shown here:
|
||||
|
||||
{% capture whatsnext %}
|
||||
|
||||
* See the `terminationMessagePath` field in
|
||||
* See the `terminationMessagePath` field in
|
||||
[Container](/docs/api-reference/v1/definitions#_v1_container).
|
||||
* Learn about [retrieving logs](/docs/user-guide/logging/).
|
||||
* Learn about [Go templates](https://golang.org/pkg/text/template/).
|
||||
|
||||
@@ -72,7 +72,7 @@ redirect_from:
|
||||
|
||||
<div class="row">
|
||||
<div class="col-md-8">
|
||||
<p><b>The Master is responsible for managing the cluster.</b> The master coordinates all activity in your cluster, such as scheduling applications, maintaining applications' desired state, scaling applications, and rolling out new updates.</p>
|
||||
<p><b>The Master is responsible for managing the cluster.</b> The master coordinates all activities in your cluster, such as scheduling applications, maintaining applications' desired state, scaling applications, and rolling out new updates.</p>
|
||||
<p><b>A node is a VM or a physical computer that serves as a worker machine in a Kubernetes cluster.</b> Each node has a Kubelet, which is an agent for managing the node and communicating with the Kubernetes master. The node should also have tools for handling container operations, such as Docker or rkt. A Kubernetes cluster that handles production traffic should have a minimum of three nodes.</p>
|
||||
|
||||
</div>
|
||||
@@ -87,7 +87,7 @@ redirect_from:
|
||||
<div class="col-md-8">
|
||||
<p>When you deploy applications on Kubernetes, you tell the master to start the application containers. The master schedules the containers to run on the cluster's nodes. <b>The nodes communicate with the master using the Kubernetes API</b>, which the master exposes. End users can also use the Kubernetes API directly to interact with the cluster.</p>
|
||||
|
||||
<p>A Kubernetes cluster can be deployed on either physical or virtual machines. To get started with Kubernetes development, you can use <a href="https://github.com/kubernetes/minikube">minikube</a>. Minikube is a lightweight Kubernetes implementation that creates a VM on your local machine and deploys a simple cluster containing only one node. Minikube is available for Linux, Mac OS and Windows systems. The minikube CLI provides basic bootstrapping operations for working with your cluster, including start, stop, status, and delete. For this bootcamp, however, you'll use a provided online terminal with minikube pre-installed.</p>
|
||||
<p>A Kubernetes cluster can be deployed on either physical or virtual machines. To get started with Kubernetes development, you can use <a href="https://github.com/kubernetes/minikube">Minikube</a>. Minikube is a lightweight Kubernetes implementation that creates a VM on your local machine and deploys a simple cluster containing only one node. Minikube is available for Linux, Mac OS and Windows systems. The Minikube CLI provides basic bootstrapping operations for working with your cluster, including start, stop, status, and delete. For this bootcamp, however, you'll use a provided online terminal with Minikube pre-installed.</p>
|
||||
|
||||
<p>Now that you know what Kubernetes is, let’s go to the online tutorial and start our first cluster!</p>
|
||||
|
||||
|
||||
@@ -70,7 +70,7 @@
|
||||
|
||||
<p>You can create and manage a Deployment by using the Kubernetes command line interface, <b>Kubectl</b>. Kubectl uses the Kubernetes API to interact with the cluster. In this module, you'll learn the most common Kubectl commands needed to create Deployments that run your applications on a Kubernetes cluster.</p>
|
||||
|
||||
<p>When you create a Deployment, you'll need to specify the container image for your application and the number of replicas that you want to run. You can change that information later by updating your Deployment; Modules <a href="5-0.html">5</a> and <a href="5-0.html">6</a> of the bootcamp discuss how you can update your Deployments.</p>
|
||||
<p>When you create a Deployment, you'll need to specify the container image for your application and the number of replicas that you want to run. You can change that information later by updating your Deployment; Modules <a href="/docs/tutorials/kubernetes-basics/scale-intro/">5</a> and <a href="/docs/tutorials/kubernetes-basics/update-intro/">6</a> of the bootcamp discuss how you can scale and update your Deployments.</p>
|
||||
|
||||
|
||||
|
||||
@@ -85,7 +85,7 @@
|
||||
|
||||
<div class="row">
|
||||
<div class="col-md-8">
|
||||
<p>For our first Deployment, we’ll use a <a href="https://nodejs.org">NodeJS</a> application packaged in a Docker container. The source code and the Dockerfile are available in the <a href="https://github.com/kubernetes/kubernetes-bootcamp">GitHub repository</a> for the Kubernetes Bootcamp.</p>
|
||||
<p>For our first Deployment, we’ll use a <a href="https://nodejs.org">Node.js</a> application packaged in a Docker container. The source code and the Dockerfile are available in the <a href="https://github.com/kubernetes/kubernetes-bootcamp">GitHub repository</a> for the Kubernetes Bootcamp.</p>
|
||||
|
||||
<p>Now that you know what Deployments are, let’s go to the online tutorial and deploy our first app!</p>
|
||||
|
||||
|
||||
@@ -27,7 +27,7 @@
|
||||
|
||||
<div class="col-md-8">
|
||||
<h2>Kubernetes Pods</h2>
|
||||
<p>When you created a Deployment in Module <a href="/docs/tutorials/kubernetes-basics/deploy-app.html">2</a>, Kubernetes created a <b>Pod</b> to host your application instance. A Pod is Kubernetes abstraction that represents a group of one or more application containers (such as Docker or rkt), and some shared resources for those containers. Those resources include:</p>
|
||||
<p>When you created a Deployment in Module <a href="/docs/tutorials/kubernetes-basics/deploy-intro/">2</a>, Kubernetes created a <b>Pod</b> to host your application instance. A Pod is Kubernetes abstraction that represents a group of one or more application containers (such as Docker or rkt), and some shared resources for those containers. Those resources include:</p>
|
||||
<ul>
|
||||
<li>Shared storage, as Volumes</li>
|
||||
<li>Networking, as a unique cluster IP address</li>
|
||||
@@ -106,7 +106,7 @@
|
||||
<div class="row">
|
||||
<div class="col-md-8">
|
||||
<h2>Troubleshooting with kubectl</h2>
|
||||
<p>In Module <a href="2-0.html">2</a>, you used Kubectl command-line interface. You'll continue to use it in Module 3 to get information about deployed applications and their environments. The most common operations can be done with the following kubectl commands:</p>
|
||||
<p>In Module <a href="/docs/tutorials/kubernetes-basics/deploy-intro/">2</a>, you used Kubectl command-line interface. You'll continue to use it in Module 3 to get information about deployed applications and their environments. The most common operations can be done with the following kubectl commands:</p>
|
||||
<ul>
|
||||
<li><b>kubectl get</b> - list resources</li>
|
||||
<li><b>kubectl describe</b> - show detailed information about a resource</li>
|
||||
@@ -114,7 +114,7 @@
|
||||
<li><b>kubectl exec</b> - execute a command on a container in a pod</li>
|
||||
</ul>
|
||||
|
||||
<p>You can use these commands to see when applications were deployed, what their current status is, where they are running and what their configuration is.</p>
|
||||
<p>You can use these commands to see when applications were deployed, what their current statuses are, where they are running and what their configurations are.</p>
|
||||
|
||||
<p>Now that we know more about our cluster components and the command line, let’s explore our application.</p>
|
||||
|
||||
|
||||
@@ -71,7 +71,7 @@
|
||||
|
||||
<p>A Service provides load balancing of traffic across the contained set of Pods. This is useful when a service is created to group all Pods from a specific Deployment (our application will make use of this in the next module, when we’ll have multiple instances running).</p>
|
||||
|
||||
<p>Services are also responsible for service-discovery within the cluster (covered in Module 6). This will for example allow a frontend service (like a web server) to receive traffic from a backend service (like a database) without worrying about Pods.</p>
|
||||
<p>Services are also responsible for service-discovery within the cluster (covered in <a href="/docs/user-guide/connecting-applications/#accessing-the-service">Accessing the Service</a>). This will for example allow a frontend service (like a web server) to receive traffic from a backend service (like a database) without worrying about Pods.</p>
|
||||
|
||||
<p>Services match a set of Pods using Label Selectors, a grouping primitive that allows logical operation on Labels.</p>
|
||||
|
||||
@@ -119,7 +119,7 @@
|
||||
<p>Labels can be attached to objects at the creation time or later and can be modified at any time.
|
||||
The kubectl run command sets some default Labels/Label Selectors on the new Pods/ Deployment. The link between Labels and Label Selectors defines the relationship between the Deployment and the Pods it creates.</p>
|
||||
|
||||
<p>Let’s expose now our application with the help of a Service, and apply some new Labels.</p>
|
||||
<p>Now let’s expose our application with the help of a Service, and apply some new Labels.</p>
|
||||
</div>
|
||||
</div>
|
||||
<br>
|
||||
|
||||
@@ -25,7 +25,7 @@
|
||||
<div class="col-md-8">
|
||||
<h3>Scaling an application</h3>
|
||||
|
||||
<p>In the previous modules we created a <a href="http://kubernetes.io/docs/user-guide/deployments/"> Deployment</a>, and then exposed it publicly via a <a href="http://kubernetes.io/docs/user-guide/services/"> Service </a>. The Deployment created only one Pod for running our application. When traffic increases, we will need to scale the application to keep up with user demand.</p>
|
||||
<p>In the previous modules we created a <a href="http://kubernetes.io/docs/user-guide/deployments/"> Deployment</a>, and then exposed it publicly via a <a href="http://kubernetes.io/docs/user-guide/services/">Service</a>. The Deployment created only one Pod for running our application. When traffic increases, we will need to scale the application to keep up with user demand.</p>
|
||||
|
||||
<p><b>Scaling</b> is accomplished by changing the number of replicas in a Deployment</p>
|
||||
|
||||
|
||||
@@ -25,10 +25,10 @@
|
||||
<div class="col-md-8">
|
||||
<h3>Updating an application</h3>
|
||||
|
||||
<p>Users expect applications to be available all the time and developers are expected to deploy new versions of them several times a day. In Kubernetes this is done with rolling updates. <b>Rolling updates</b> allows Deployments to occur with zero downtime by incrementally updating Pods instances with new ones. The new Pods will be scheduled on Nodes with available resources.</p>
|
||||
<p>Users expect applications to be available all the time and developers are expected to deploy new versions of them several times a day. In Kubernetes this is done with rolling updates. <b>Rolling updates</b> allow Deployments' update to take place with zero downtime by incrementally updating Pods instances with new ones. The new Pods will be scheduled on Nodes with available resources.</p>
|
||||
|
||||
<p>In the previous module we scaled our application to run multiple instances. This is a requirement for performing updates without affecting application availability. By default, the maximum number of Pods that can be unavailable during the update and the maximum number of new Pods that can be created, is one. Both options can be configured to either numbers or percentages (of Pods).
|
||||
In Kubernetes, updates are versioned and any Deployment update can be reverted to a previously (stable) version.</p>
|
||||
In Kubernetes, updates are versioned and any Deployment update can be reverted to previous (stable) version.</p>
|
||||
|
||||
</div>
|
||||
<div class="col-md-4">
|
||||
@@ -39,7 +39,7 @@
|
||||
</ul>
|
||||
</div>
|
||||
<div class="content__box content__box_fill">
|
||||
<p><i>Rolling updates allows Deployments update with zero downtime by incrementally updating Pods instances with new ones. </i></p>
|
||||
<p><i>Rolling updates allow Deployments' update to take place with zero downtime by incrementally updating Pods instances with new ones. </i></p>
|
||||
</div>
|
||||
</div>
|
||||
</div>
|
||||
|
||||
@@ -103,7 +103,7 @@ provides load balancing for an application that has two running instances.
|
||||
|
||||
curl http://<public-node-ip>:<node-port>
|
||||
|
||||
where `<public-node-ip>` us the public IP address of your node,
|
||||
where `<public-node-ip>` is the public IP address of your node,
|
||||
and `<node-port>` is the NodePort value for your service.
|
||||
|
||||
The response to a successful request is a hello message:
|
||||
|
||||
@@ -64,7 +64,7 @@ external IP address.
|
||||
NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
|
||||
my-service 10.3.245.137 104.198.205.71 8080/TCP 54s
|
||||
|
||||
Note: If the external IP address is shown as <pending>, wait for a minute
|
||||
Note: If the external IP address is shown as \<pending\>, wait for a minute
|
||||
and enter the same command again.
|
||||
|
||||
1. Display detailed information about the Service:
|
||||
@@ -110,7 +110,7 @@ external IP address.
|
||||
|
||||
curl http://<external-ip>:<port>
|
||||
|
||||
where `<external-ip>` us the external IP address of your Service,
|
||||
where `<external-ip>` is the external IP address of your Service,
|
||||
and `<port>` is the value of `Port` in your Service description.
|
||||
|
||||
The response to a successful request is a hello message:
|
||||
|
||||
@@ -37,8 +37,7 @@ a Deployment that runs the nginx:1.7.9 Docker image:
|
||||
|
||||
1. Create a Deployment based on the YAML file:
|
||||
|
||||
export REPO=https://raw.githubusercontent.com/kubernetes/kubernetes.github.io/master
|
||||
kubectl create -f $REPO/docs/tutorials/stateless-application/deployment.yaml
|
||||
kubectl create -f http://k8s.io/docs/tutorials/stateless-application/deployment.yaml
|
||||
|
||||
1. Display information about the Deployment:
|
||||
|
||||
@@ -81,7 +80,7 @@ specifies that the deployment should be updated to use nginx 1.8.
|
||||
|
||||
1. Apply the new YAML file:
|
||||
|
||||
kubectl apply -f $REPO/docs/tutorials/stateless-application/deployment-update.yaml
|
||||
kubectl apply -f http://k8s.io/docs/tutorials/stateless-application/deployment-update.yaml
|
||||
|
||||
1. Watch the deployment create pods with new names and delete the old pods:
|
||||
|
||||
@@ -97,7 +96,7 @@ should have four pods:
|
||||
|
||||
1. Apply the new YAML file:
|
||||
|
||||
kubectl apply -f $REPO/docs/tutorials/stateless-application/deployment-scale.yaml
|
||||
kubectl apply -f http://k8s.io/docs/tutorials/stateless-application/deployment-scale.yaml
|
||||
|
||||
1. Verify that the Deployment has four pods:
|
||||
|
||||
|
||||
@@ -21,7 +21,7 @@ This document is meant to highlight and consolidate in one place configuration b
|
||||
- Don't specify default values unnecessarily, in order to simplify and minimize configs, and to
|
||||
reduce error. For example, omit the selector and labels in a `ReplicationController` if you want
|
||||
them to be the same as the labels in its `podTemplate`, since those fields are populated from the
|
||||
`podTemplate` labels by default. See the [guestbook app's](https://github.com/kubernetes/kubernetes/tree/{{page.githubbranch}}/examples/guestbook/) .yaml files for some [examples](https://github.com/kubernetes/kubernetes/tree/{{page.githubbranch}}/examples/guestbook/frontend-controller.yaml) of this.
|
||||
`podTemplate` labels by default. See the [guestbook app's](https://github.com/kubernetes/kubernetes/tree/{{page.githubbranch}}/examples/guestbook/) .yaml files for some [examples](https://github.com/kubernetes/kubernetes/tree/{{page.githubbranch}}/examples/guestbook/frontend-deployment.yaml) of this.
|
||||
|
||||
- Put an object description in an annotation to allow better introspection.
|
||||
|
||||
|
||||
@@ -99,10 +99,10 @@ _Set-based_ requirements can be mixed with _equality-based_ requirements. For ex
|
||||
|
||||
### LIST and WATCH filtering
|
||||
|
||||
LIST and WATCH operations may specify label selectors to filter the sets of objects returned using a query parameter. Both requirements are permitted:
|
||||
LIST and WATCH operations may specify label selectors to filter the sets of objects returned using a query parameter. Both requirements are permitted (presented here as they would appear in a URL query string):
|
||||
|
||||
* _equality-based_ requirements: `?labelSelector=environment%3Dproduction,tier%3Dfrontend`
|
||||
* _set-based_ requirements: `?labelSelector=environment+in+%28production%2Cqa%29%2Ctier+in+%28frontend%29`
|
||||
* _equality-based_ requirements: `?labelSelector=environment%3Dproduction,tier%3Dfrontend`
|
||||
* _set-based_ requirements: `?labelSelector=environment+in+%28production%2Cqa%29%2Ctier+in+%28frontend%29`
|
||||
|
||||
Both label selector styles can be used to list or watch resources via a REST client. For example, targeting `apiserver` with `kubectl` and using _equality-based_ one may write:
|
||||
|
||||
|
||||
@@ -204,7 +204,7 @@ The status of the init containers is returned as another annotation - `pod.beta.
|
||||
|
||||
Init containers support all of the same features as normal containers, including resource limits, volumes, and security settings. The resource requests and limits for an init container are handled slightly different than normal containers since init containers are run one at a time instead of all at once - any limits or quotas will be applied based on the largest init container resource quantity, rather than as the sum of quantities. Init containers do not support readiness probes since they will run to completion before the pod can be ready.
|
||||
|
||||
[Complete Init Container Documentation](/docs/user-guide/pods/init-containers.md)
|
||||
[Complete Init Container Documentation](/docs/user-guide/pods/init-container/)
|
||||
|
||||
|
||||
## Lifecycle hooks and termination notice
|
||||
|
||||
@@ -176,7 +176,7 @@ its pods, add appropriate selectors or endpoints and change the service `type`.
|
||||
## Virtual IPs and service proxies
|
||||
|
||||
Every node in a Kubernetes cluster runs a `kube-proxy`. `kube-proxy` is
|
||||
responsible for implementing a form of virtual IP for `Service`s of type other
|
||||
responsible for implementing a form of virtual IP for `Services` of type other
|
||||
than `ExternalName`.
|
||||
In Kubernetes v1.0 the proxy was purely in userspace. In Kubernetes v1.1 an
|
||||
iptables proxy was added, but was not the default operating mode. Since
|
||||
|
||||
Reference in New Issue
Block a user