Merge pull request #1144 from adieu/format
Some small style tweaks to make pandoc working
This commit is contained in:
devin-donnelly
@@ -9,7 +9,7 @@ assignees:
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* TOC
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{:toc}
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# The Kubernetes model for connecting containers
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## The Kubernetes model for connecting containers
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Now that you have a continuously running, replicated application you can expose it on a network. Before discussing the Kubernetes approach to networking, it is worthwhile to contrast it with the "normal" way networking works with Docker.
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@@ -1,50 +1,50 @@
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---
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assignees:
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- caesarxuchao
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- mikedanese
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---
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kubectl port-forward forwards connections to a local port to a port on a pod. Its man page is available [here](/docs/user-guide/kubectl/kubectl_port-forward). Compared to [kubectl proxy](/docs/user-guide/accessing-the-cluster/#using-kubectl-proxy), `kubectl port-forward` is more generic as it can forward TCP traffic while `kubectl proxy` can only forward HTTP traffic. This guide demonstrates how to use `kubectl port-forward` to connect to a Redis database, which may be useful for database debugging.
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## Creating a Redis master
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```shell
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$ kubectl create -f examples/redis/redis-master.yaml
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pods/redis-master
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```
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wait until the Redis master pod is Running and Ready,
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```shell
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$ kubectl get pods
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NAME READY STATUS RESTARTS AGE
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redis-master 2/2 Running 0 41s
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```
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## Connecting to the Redis master[a]
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The Redis master is listening on port 6379, to verify this,
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```shell{% raw %}
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$ kubectl get pods redis-master --template='{{(index (index .spec.containers 0).ports 0).containerPort}}{{"\n"}}'
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6379{% endraw %}
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```
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then we forward the port 6379 on the local workstation to the port 6379 of pod redis-master,
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```shell
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$ kubectl port-forward redis-master 6379:6379
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I0710 14:43:38.274550 3655 portforward.go:225] Forwarding from 127.0.0.1:6379 -> 6379
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I0710 14:43:38.274797 3655 portforward.go:225] Forwarding from [::1]:6379 -> 6379
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```
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To verify the connection is successful, we run a redis-cli on the local workstation,
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```shell
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$ redis-cli
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127.0.0.1:6379> ping
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PONG
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```
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Now one can debug the database from the local workstation.
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---
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assignees:
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- caesarxuchao
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- mikedanese
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---
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|
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kubectl port-forward forwards connections to a local port to a port on a pod. Its man page is available [here](/docs/user-guide/kubectl/kubectl_port-forward). Compared to [kubectl proxy](/docs/user-guide/accessing-the-cluster/#using-kubectl-proxy), `kubectl port-forward` is more generic as it can forward TCP traffic while `kubectl proxy` can only forward HTTP traffic. This guide demonstrates how to use `kubectl port-forward` to connect to a Redis database, which may be useful for database debugging.
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## Creating a Redis master
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```shell
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$ kubectl create -f examples/redis/redis-master.yaml
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pods/redis-master
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```
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wait until the Redis master pod is Running and Ready,
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```shell
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$ kubectl get pods
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NAME READY STATUS RESTARTS AGE
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redis-master 2/2 Running 0 41s
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```
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## Connecting to the Redis master[a]
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The Redis master is listening on port 6379, to verify this,
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```shell{% raw %}
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$ kubectl get pods redis-master --template='{{(index (index .spec.containers 0).ports 0).containerPort}}{{"\n"}}'
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6379{% endraw %}
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```
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then we forward the port 6379 on the local workstation to the port 6379 of pod redis-master,
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```shell
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$ kubectl port-forward redis-master 6379:6379
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I0710 14:43:38.274550 3655 portforward.go:225] Forwarding from 127.0.0.1:6379 -> 6379
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I0710 14:43:38.274797 3655 portforward.go:225] Forwarding from [::1]:6379 -> 6379
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```
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To verify the connection is successful, we run a redis-cli on the local workstation,
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|
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```shell
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$ redis-cli
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127.0.0.1:6379> ping
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PONG
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```
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Now one can debug the database from the local workstation.
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@@ -1,32 +1,32 @@
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---
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assignees:
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- caesarxuchao
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- lavalamp
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---
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You have seen the [basics](/docs/user-guide/accessing-the-cluster) about `kubectl proxy` and `apiserver proxy`. This guide shows how to use them together to access a service([kube-ui](/docs/user-guide/ui)) running on the Kubernetes cluster from your workstation.
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## Getting the apiserver proxy URL of kube-ui
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kube-ui is deployed as a cluster add-on. To find its apiserver proxy URL,
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```shell
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$ kubectl cluster-info | grep "KubeUI"
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KubeUI is running at https://173.255.119.104/api/v1/proxy/namespaces/kube-system/services/kube-ui
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```
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if this command does not find the URL, try the steps [here](/docs/user-guide/ui/#accessing-the-ui).
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## Connecting to the kube-ui service from your local workstation
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The above proxy URL is an access to the kube-ui service provided by the apiserver. To access it, you still need to authenticate to the apiserver. `kubectl proxy` can handle the authentication.
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```shell
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$ kubectl proxy --port=8001
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Starting to serve on localhost:8001
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```
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---
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assignees:
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- caesarxuchao
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||||
- lavalamp
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|
||||
---
|
||||
|
||||
You have seen the [basics](/docs/user-guide/accessing-the-cluster) about `kubectl proxy` and `apiserver proxy`. This guide shows how to use them together to access a service([kube-ui](/docs/user-guide/ui)) running on the Kubernetes cluster from your workstation.
|
||||
|
||||
|
||||
## Getting the apiserver proxy URL of kube-ui
|
||||
|
||||
kube-ui is deployed as a cluster add-on. To find its apiserver proxy URL,
|
||||
|
||||
```shell
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$ kubectl cluster-info | grep "KubeUI"
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KubeUI is running at https://173.255.119.104/api/v1/proxy/namespaces/kube-system/services/kube-ui
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```
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if this command does not find the URL, try the steps [here](/docs/user-guide/ui/#accessing-the-ui).
|
||||
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## Connecting to the kube-ui service from your local workstation
|
||||
|
||||
The above proxy URL is an access to the kube-ui service provided by the apiserver. To access it, you still need to authenticate to the apiserver. `kubectl proxy` can handle the authentication.
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|
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```shell
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$ kubectl proxy --port=8001
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Starting to serve on localhost:8001
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||||
```
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Now you can access the kube-ui service on your local workstation at [http://localhost:8001/api/v1/proxy/namespaces/kube-system/services/kube-ui](http://localhost:8001/api/v1/proxy/namespaces/kube-system/services/kube-ui)
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@@ -1,74 +1,74 @@
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---
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assignees:
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- caesarxuchao
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||||
- mikedanese
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---
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||||
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Developers can use `kubectl exec` to run commands in a container. This guide demonstrates two use cases.
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## Using kubectl exec to check the environment variables of a container
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|
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Kubernetes exposes [services](/docs/user-guide/services/#environment-variables) through environment variables. It is convenient to check these environment variables using `kubectl exec`.
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||||
|
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We first create a pod and a service,
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|
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```shell
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$ kubectl create -f examples/guestbook/redis-master-controller.yaml
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$ kubectl create -f examples/guestbook/redis-master-service.yaml
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```
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wait until the pod is Running and Ready,
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```shell
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$ kubectl get pod
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NAME READY REASON RESTARTS AGE
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redis-master-ft9ex 1/1 Running 0 12s
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```
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then we can check the environment variables of the pod,
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```shell
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$ kubectl exec redis-master-ft9ex env
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...
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REDIS_MASTER_SERVICE_PORT=6379
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REDIS_MASTER_SERVICE_HOST=10.0.0.219
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...
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```
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We can use these environment variables in applications to find the service.
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## Using kubectl exec to check the mounted volumes
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It is convenient to use `kubectl exec` to check if the volumes are mounted as expected.
|
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We first create a Pod with a volume mounted at /data/redis,
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|
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```shell
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kubectl create -f docs/user-guide/walkthrough/pod-redis.yaml
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```
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wait until the pod is Running and Ready,
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|
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```shell
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$ kubectl get pods
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NAME READY REASON RESTARTS AGE
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storage 1/1 Running 0 1m
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```
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we then use `kubectl exec` to verify that the volume is mounted at /data/redis,
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|
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```shell
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$ kubectl exec storage ls /data
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redis
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```
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|
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## Using kubectl exec to open a bash terminal in a pod
|
||||
|
||||
After all, open a terminal in a pod is the most direct way to introspect the pod. Assuming the pod/storage is still running, run
|
||||
|
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```shell
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$ kubectl exec -ti storage -- bash
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root@storage:/data#
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```
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|
||||
---
|
||||
assignees:
|
||||
- caesarxuchao
|
||||
- mikedanese
|
||||
|
||||
---
|
||||
|
||||
Developers can use `kubectl exec` to run commands in a container. This guide demonstrates two use cases.
|
||||
|
||||
## Using kubectl exec to check the environment variables of a container
|
||||
|
||||
Kubernetes exposes [services](/docs/user-guide/services/#environment-variables) through environment variables. It is convenient to check these environment variables using `kubectl exec`.
|
||||
|
||||
We first create a pod and a service,
|
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|
||||
```shell
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$ kubectl create -f examples/guestbook/redis-master-controller.yaml
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$ kubectl create -f examples/guestbook/redis-master-service.yaml
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```
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wait until the pod is Running and Ready,
|
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|
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```shell
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$ kubectl get pod
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NAME READY REASON RESTARTS AGE
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redis-master-ft9ex 1/1 Running 0 12s
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```
|
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|
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then we can check the environment variables of the pod,
|
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|
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```shell
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$ kubectl exec redis-master-ft9ex env
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...
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REDIS_MASTER_SERVICE_PORT=6379
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REDIS_MASTER_SERVICE_HOST=10.0.0.219
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...
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```
|
||||
|
||||
We can use these environment variables in applications to find the service.
|
||||
|
||||
|
||||
## Using kubectl exec to check the mounted volumes
|
||||
|
||||
It is convenient to use `kubectl exec` to check if the volumes are mounted as expected.
|
||||
We first create a Pod with a volume mounted at /data/redis,
|
||||
|
||||
```shell
|
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kubectl create -f docs/user-guide/walkthrough/pod-redis.yaml
|
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```
|
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|
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wait until the pod is Running and Ready,
|
||||
|
||||
```shell
|
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$ kubectl get pods
|
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NAME READY REASON RESTARTS AGE
|
||||
storage 1/1 Running 0 1m
|
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```
|
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|
||||
we then use `kubectl exec` to verify that the volume is mounted at /data/redis,
|
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|
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```shell
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$ kubectl exec storage ls /data
|
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redis
|
||||
```
|
||||
|
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## Using kubectl exec to open a bash terminal in a pod
|
||||
|
||||
After all, open a terminal in a pod is the most direct way to introspect the pod. Assuming the pod/storage is still running, run
|
||||
|
||||
```shell
|
||||
$ kubectl exec -ti storage -- bash
|
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root@storage:/data#
|
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```
|
||||
|
||||
This gets you a terminal.
|
||||
+79
-79
@@ -1,80 +1,80 @@
|
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---
|
||||
assignees:
|
||||
- mikedanese
|
||||
|
||||
---
|
||||
|
||||
This page is designed to help you use logs to troubleshoot issues with your Kubernetes solution.
|
||||
|
||||
## Logging by Kubernetes Components
|
||||
|
||||
Kubernetes components, such as kubelet and apiserver, use the [glog](https://godoc.org/github.com/golang/glog) logging library. Developer conventions for logging severity are described in [docs/devel/logging.md](https://github.com/kubernetes/kubernetes/tree/{{page.githubbranch}}/docs/devel/logging.md).
|
||||
|
||||
## Examining the logs of running containers
|
||||
|
||||
The logs of a running container may be fetched using the command `kubectl logs`. For example, given
|
||||
this pod specification [counter-pod.yaml](https://github.com/kubernetes/kubernetes/tree/{{page.githubbranch}}/examples/blog-logging/counter-pod.yaml), which has a container which writes out some text to standard
|
||||
output every second. (You can find different pod specifications [here](https://github.com/kubernetes/kubernetes.github.io/tree/{{page.docsbranch}}/docs/user-guide/logging-demo/).)
|
||||
|
||||
{% include code.html language="yaml" file="counter-pod.yaml" k8slink="/examples/blog-logging/counter-pod.yaml" %}
|
||||
|
||||
we can run the pod:
|
||||
|
||||
```shell
|
||||
$ kubectl create -f ./counter-pod.yaml
|
||||
pods/counter
|
||||
```
|
||||
|
||||
and then fetch the logs:
|
||||
|
||||
```shell
|
||||
$ kubectl logs counter
|
||||
0: Tue Jun 2 21:37:31 UTC 2015
|
||||
1: Tue Jun 2 21:37:32 UTC 2015
|
||||
2: Tue Jun 2 21:37:33 UTC 2015
|
||||
3: Tue Jun 2 21:37:34 UTC 2015
|
||||
4: Tue Jun 2 21:37:35 UTC 2015
|
||||
5: Tue Jun 2 21:37:36 UTC 2015
|
||||
...
|
||||
```
|
||||
|
||||
If a pod has more than one container then you need to specify which container's log files should
|
||||
be fetched e.g.
|
||||
|
||||
```shell
|
||||
$ kubectl logs kube-dns-v3-7r1l9 etcd
|
||||
2015/06/23 00:43:10 etcdserver: start to snapshot (applied: 30003, lastsnap: 20002)
|
||||
2015/06/23 00:43:10 etcdserver: compacted log at index 30003
|
||||
2015/06/23 00:43:10 etcdserver: saved snapshot at index 30003
|
||||
2015/06/23 02:05:42 etcdserver: start to snapshot (applied: 40004, lastsnap: 30003)
|
||||
2015/06/23 02:05:42 etcdserver: compacted log at index 40004
|
||||
2015/06/23 02:05:42 etcdserver: saved snapshot at index 40004
|
||||
2015/06/23 03:28:31 etcdserver: start to snapshot (applied: 50005, lastsnap: 40004)
|
||||
2015/06/23 03:28:31 etcdserver: compacted log at index 50005
|
||||
2015/06/23 03:28:31 etcdserver: saved snapshot at index 50005
|
||||
2015/06/23 03:28:56 filePurge: successfully removed file default.etcd/member/wal/0000000000000000-0000000000000000.wal
|
||||
2015/06/23 04:51:03 etcdserver: start to snapshot (applied: 60006, lastsnap: 50005)
|
||||
2015/06/23 04:51:03 etcdserver: compacted log at index 60006
|
||||
2015/06/23 04:51:03 etcdserver: saved snapshot at index 60006
|
||||
...
|
||||
```
|
||||
|
||||
## Cluster level logging to Google Cloud Logging
|
||||
|
||||
The getting started guide [Cluster Level Logging to Google Cloud Logging](/docs/getting-started-guides/logging)
|
||||
explains how container logs are ingested into [Google Cloud Logging](https://cloud.google.com/logging/docs/)
|
||||
and shows how to query the ingested logs.
|
||||
|
||||
## Cluster level logging with Elasticsearch and Kibana
|
||||
|
||||
The getting started guide [Cluster Level Logging with Elasticsearch and Kibana](/docs/getting-started-guides/logging-elasticsearch)
|
||||
describes how to ingest cluster level logs into Elasticsearch and view them using Kibana.
|
||||
|
||||
## Ingesting Application Log Files
|
||||
|
||||
Cluster level logging only collects the standard output and standard error output of the applications
|
||||
running in containers. The guide [Collecting log files from within containers with Fluentd and sending them to the Google Cloud Logging service](https://github.com/kubernetes/contrib/blob/master/logging/fluentd-sidecar-gcp/README.md) explains how the log files of applications can also be ingested into Google Cloud logging.
|
||||
|
||||
## Known issues
|
||||
|
||||
---
|
||||
assignees:
|
||||
- mikedanese
|
||||
|
||||
---
|
||||
|
||||
This page is designed to help you use logs to troubleshoot issues with your Kubernetes solution.
|
||||
|
||||
## Logging by Kubernetes Components
|
||||
|
||||
Kubernetes components, such as kubelet and apiserver, use the [glog](https://godoc.org/github.com/golang/glog) logging library. Developer conventions for logging severity are described in [docs/devel/logging.md](https://github.com/kubernetes/kubernetes/tree/{{page.githubbranch}}/docs/devel/logging.md).
|
||||
|
||||
## Examining the logs of running containers
|
||||
|
||||
The logs of a running container may be fetched using the command `kubectl logs`. For example, given
|
||||
this pod specification [counter-pod.yaml](https://github.com/kubernetes/kubernetes/tree/{{page.githubbranch}}/examples/blog-logging/counter-pod.yaml), which has a container which writes out some text to standard
|
||||
output every second. (You can find different pod specifications [here](https://github.com/kubernetes/kubernetes.github.io/tree/{{page.docsbranch}}/docs/user-guide/logging-demo/).)
|
||||
|
||||
{% include code.html language="yaml" file="counter-pod.yaml" k8slink="/examples/blog-logging/counter-pod.yaml" %}
|
||||
|
||||
we can run the pod:
|
||||
|
||||
```shell
|
||||
$ kubectl create -f ./counter-pod.yaml
|
||||
pods/counter
|
||||
```
|
||||
|
||||
and then fetch the logs:
|
||||
|
||||
```shell
|
||||
$ kubectl logs counter
|
||||
0: Tue Jun 2 21:37:31 UTC 2015
|
||||
1: Tue Jun 2 21:37:32 UTC 2015
|
||||
2: Tue Jun 2 21:37:33 UTC 2015
|
||||
3: Tue Jun 2 21:37:34 UTC 2015
|
||||
4: Tue Jun 2 21:37:35 UTC 2015
|
||||
5: Tue Jun 2 21:37:36 UTC 2015
|
||||
...
|
||||
```
|
||||
|
||||
If a pod has more than one container then you need to specify which container's log files should
|
||||
be fetched e.g.
|
||||
|
||||
```shell
|
||||
$ kubectl logs kube-dns-v3-7r1l9 etcd
|
||||
2015/06/23 00:43:10 etcdserver: start to snapshot (applied: 30003, lastsnap: 20002)
|
||||
2015/06/23 00:43:10 etcdserver: compacted log at index 30003
|
||||
2015/06/23 00:43:10 etcdserver: saved snapshot at index 30003
|
||||
2015/06/23 02:05:42 etcdserver: start to snapshot (applied: 40004, lastsnap: 30003)
|
||||
2015/06/23 02:05:42 etcdserver: compacted log at index 40004
|
||||
2015/06/23 02:05:42 etcdserver: saved snapshot at index 40004
|
||||
2015/06/23 03:28:31 etcdserver: start to snapshot (applied: 50005, lastsnap: 40004)
|
||||
2015/06/23 03:28:31 etcdserver: compacted log at index 50005
|
||||
2015/06/23 03:28:31 etcdserver: saved snapshot at index 50005
|
||||
2015/06/23 03:28:56 filePurge: successfully removed file default.etcd/member/wal/0000000000000000-0000000000000000.wal
|
||||
2015/06/23 04:51:03 etcdserver: start to snapshot (applied: 60006, lastsnap: 50005)
|
||||
2015/06/23 04:51:03 etcdserver: compacted log at index 60006
|
||||
2015/06/23 04:51:03 etcdserver: saved snapshot at index 60006
|
||||
...
|
||||
```
|
||||
|
||||
## Cluster level logging to Google Cloud Logging
|
||||
|
||||
The getting started guide [Cluster Level Logging to Google Cloud Logging](/docs/getting-started-guides/logging)
|
||||
explains how container logs are ingested into [Google Cloud Logging](https://cloud.google.com/logging/docs/)
|
||||
and shows how to query the ingested logs.
|
||||
|
||||
## Cluster level logging with Elasticsearch and Kibana
|
||||
|
||||
The getting started guide [Cluster Level Logging with Elasticsearch and Kibana](/docs/getting-started-guides/logging-elasticsearch)
|
||||
describes how to ingest cluster level logs into Elasticsearch and view them using Kibana.
|
||||
|
||||
## Ingesting Application Log Files
|
||||
|
||||
Cluster level logging only collects the standard output and standard error output of the applications
|
||||
running in containers. The guide [Collecting log files from within containers with Fluentd and sending them to the Google Cloud Logging service](https://github.com/kubernetes/contrib/blob/master/logging/fluentd-sidecar-gcp/README.md) explains how the log files of applications can also be ingested into Google Cloud logging.
|
||||
|
||||
## Known issues
|
||||
|
||||
Kubernetes does log rotation for Kubernetes components and docker containers. The command `kubectl logs` currently only read the latest logs, not all historical ones.
|
||||
@@ -6,7 +6,7 @@ assignees:
|
||||
|
||||
Understanding how an application behaves when deployed is crucial to scaling the application and providing a reliable service. In a Kubernetes cluster, application performance can be examined at many different levels: containers, [pods](/docs/user-guide/pods), [services](/docs/user-guide/services), and whole clusters. As part of Kubernetes we want to provide users with detailed resource usage information about their running applications at all these levels. This will give users deep insights into how their applications are performing and where possible application bottlenecks may be found. In comes [Heapster](https://github.com/kubernetes/heapster), a project meant to provide a base monitoring platform on Kubernetes.
|
||||
|
||||
### Overview
|
||||
## Overview
|
||||
|
||||
Heapster is a cluster-wide aggregator of monitoring and event data. It currently supports Kubernetes natively and works on all Kubernetes setups. Heapster runs as a pod in the cluster, similar to how any Kubernetes application would run. The Heapster pod discovers all nodes in the cluster and queries usage information from the nodes' [Kubelet](https://releases.k8s.io/{{page.githubbranch}}/DESIGN.md#kubelet)s, the on-machine Kubernetes agent. The Kubelet itself fetches the data from [cAdvisor](https://github.com/google/cadvisor). Heapster groups the information by pod along with the relevant labels. This data is then pushed to a configurable backend for storage and visualization. Currently supported backends include [InfluxDB](http://influxdb.com/) (with [Grafana](http://grafana.org/) for visualization), [Google Cloud Monitoring](https://cloud.google.com/monitoring/) and many others described in more details [here](https://github.com/kubernetes/heapster/blob/master/docs/sink-configuration.md). The overall architecture of the service can be seen below:
|
||||
|
||||
|
||||
Reference in New Issue
Block a user