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update dynamic kubelet config docs for v1.11 (#8766)

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* update dynamic kubelet config docs for v1.11

* Substantial copyedit

* Address feedback
This commit is contained in:
Michael Taufen
2018-06-13 10:53:28 -07:00
committed by Misty Linville
parent 0c1970eaaf
commit bf668921f4
1 changed files with 218 additions and 311 deletions
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content/en/docs/tasks/administer-cluster/reconfigure-kubelet.md
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@@ -7,31 +7,28 @@ content_template: templates/task
---
{{% capture overview %}}
{{< feature-state state="alpha" >}}
As of Kubernetes 1.8, the new
{{< feature-state for_k8s_version="v1.11" state="beta" >}}
[Dynamic Kubelet Configuration](https://github.com/kubernetes/features/issues/281)
feature is available in alpha. This allows you to change the configuration of
Kubelets in a live Kubernetes cluster via first-class Kubernetes concepts.
Specifically, this feature allows you to configure individual Nodes' Kubelets
via ConfigMaps.
allows you to change the configuration of each Kubelet in a live Kubernetes
cluster by deploying a ConfigMap and configuring each Node to use it.
{{< warning >}}
**Warning:** All Kubelet configuration parameters may be changed dynamically,
but not all parameters are safe to change dynamically. This feature is intended
for system experts who have a strong understanding of how configuration changes
will affect behavior. No documentation currently exists which plainly lists
"safe to change" fields, but we plan to add it before this feature graduates
from alpha.
**Warning:** All Kubelet configuration parameters can be changed dynamically,
but this is unsafe for some parameters. Before deciding to change a parameter
dynamically, you need a strong understanding of how that change will affect your
cluster's behavior. Always carefully test configuration changes on a small set
of nodes before rolling them out cluster-wide. Advice on configuring specific
fields is available in the inline `KubeletConfiguration`
[type documentation](https://github.com/kubernetes/kubernetes/blob/release-1.11/pkg/kubelet/apis/kubeletconfig/v1beta1/types.go).
{{< /warning >}}
{{% /capture %}}
{{% capture prerequisites %}}
- A live Kubernetes cluster with both Master and Node at v1.8 or higher must be
running, with the `DynamicKubeletConfig` feature gate enabled and the Kubelet's
`--dynamic-config-dir` flag set to a writable directory on the Node.
This flag must be set to enable Dynamic Kubelet Configuration.
- The kubectl command-line tool must be also v1.8 or higher, and must be
configured to communicate with the cluster.
- Kubernetes v1.11 or higher on both the Master and the Nodes
- kubectl v1.11 or higher, configured to communicate with the cluster
- The Kubelet's `--dynamic-config-dir` flag must be set to a writable
directory on the Node.
{{% /capture %}}
{{% capture steps %}}
@@ -50,20 +47,19 @@ Kubelet's configuration.
Each Kubelet watches a configuration reference on its respective Node object.
When this reference changes, the Kubelet downloads the new configuration,
updates a local reference to refer to the file, and exits.
For the feature to work correctly, you must be running a process manager
(like systemd) which will restart the Kubelet when it exits. When the Kubelet is
restarted, it will begin using the new configuration.
For the feature to work correctly, you must be running an OS-level service
manager (such as systemd), which will restart the Kubelet if it exits. When the
Kubelet is restarted, it will begin using the new configuration.
The new configuration completely overrides configuration provided by `--config`,
and is overridden by command-line flags. Unspecified values in the new configuration
will receive default values appropriate to the configuration version
(e.g. `kubelet.config.k8s.io/v1beta1`), unless overridden by flags.
The status of the Node's Kubelet configuration is reported via the `KubeletConfigOK`
condition in the Node status. Once you have updated a Node to use the new
ConfigMap, you can observe this condition to confirm that the Node is using the
intended configuration. A table describing the possible conditions can be found
at the end of this article.
The status of the Node's Kubelet configuration is reported via
`Node.Spec.Status.Config`. Once you have updated a Node to use the new
ConfigMap, you can observe this status to confirm that the Node is using the
intended configuration.
This document describes editing Nodes using `kubectl edit`.
There are other ways to modify a Node's spec, including `kubectl patch`, for
@@ -72,16 +68,19 @@ example, which facilitate scripted workflows.
This document only describes a single Node consuming each ConfigMap. Keep in
mind that it is also valid for multiple Nodes to consume the same ConfigMap.
### Node Authorizer Workarounds
{{< warning >}}
**Warning:** While it is *possible* to change the configuration by
updating the ConfigMap in-place, this causes all Kubelets configured with
that ConfigMap to update simultaneously. It is much safer to treat ConfigMaps
as immutable by convention, aided by `kubectl`'s `--append-hash` option,
and incrementally roll out updates to `Node.Spec.ConfigSource`.
{{< /warning >}}
The Node Authorizer does not yet pay attention to which ConfigMaps are assigned
to which Nodes. If you currently use the Node authorizer, your Kubelets will not
be automatically granted permission to download their respective ConfigMaps.
### Automatic RBAC rules for Node Authorizer
The temporary workaround used in this document is to manually create the RBAC
Roles and RoleBindings for each ConfigMap. The Node Authorizer will be extended
before the Dynamic Kubelet Configuration feature graduates from alpha, so doing
this in production should never be necessary.
Previously, you were required to manually create RBAC rules
to allow Nodes to access their assigned ConfigMaps. The Node Authorizer now
automatically configures these rules.
### Generating a file that contains the current configuration
@@ -92,54 +91,62 @@ and debug issues. The compromise, however, is that you must start with knowledge
of the existing configuration to ensure that you only change the fields you
intend to change.
In the future, the Kubelet will be bootstrapped from a file on disk
Ideally, the Kubelet would be bootstrapped from a file on disk
and you could edit this file (which could also be version-controlled),
to create the first Kubelet ConfigMap
(see [Set Kubelet parameters via a config file](/docs/tasks/administer-cluster/kubelet-config-file)),
and you will simply edit a copy of this file (which, as a best practice, should
live in version control) while creating the first Kubelet ConfigMap. Today,
however, the Kubelet is still bootstrapped with command-line flags. Fortunately,
there is a dirty trick you can use to generate a config file containing a Node's
current configuration. The trick involves accessing the Kubelet server's `configz`
endpoint via the kubectl proxy. This endpoint, in its current implementation, is
intended to be used only as a debugging aid, which is part of why this is a
dirty trick. The endpoint may be improved in the future, but until then
it should not be relied on for production scenarios.
This trick also requires the `jq` command to be installed on your machine,
for unpacking and editing the JSON response from the endpoint.
Currently, the Kubelet is bootstrapped with **a combination of this file and command-line flags**
that can override the configuration in the file.
As a workaround, you can generate a config file containing a Node's current
configuration by accessing the Kubelet server's `configz` endpoint via the
kubectl proxy. This endpoint, in its current implementation, is intended to be
used only as a debugging aid. Do not rely on the behavior of this endpoint for
production scenarios. The examples below use the `jq` command to streamline
working with JSON. To follow the tasks as written, you need to have `jq`
installed, but you can adapt the tasks if you prefer to extract the
`kubeletconfig` subobject manually.
Do the following to generate the file:
#### Generate the configuration file
1. Pick a Node to reconfigure. We will refer to this Node's name as NODE_NAME.
2. Start the kubectl proxy in the background with `kubectl proxy --port=8001 &`
3. Run the following command to download and unpack the configuration from the
configz endpoint:
1. Choose a Node to reconfigure. In this example, the name of this Node is
referred to as `NODE_NAME`.
2. Start the kubectl proxy in the background using the following command:
```bash
kubectl proxy --port=8001 &
```
3. Run the following command to download and unpack the configuration from the
`configz` endpoint. The command is long, so be careful when copying and
pasting. **If you use zsh**, replace the `${NODE_NAME}` in the URL with the
actual name of the node, because zsh automatically escapes opening curly
braces, which causes the command to fail.
```
$ export NODE_NAME=the-name-of-the-node-you-are-reconfiguring
$ curl -sSL http://localhost:8001/api/v1/nodes/${NODE_NAME}/proxy/configz | jq '.kubeletconfig|.kind="KubeletConfiguration"|.apiVersion="kubelet.config.k8s.io/v1beta1"' > kubelet_configz_${NODE_NAME}
```
```bash
NODE_NAME="the-name-of-the-node-you-are-reconfiguring"; curl -sSL "http://localhost:8001/api/v1/nodes/${NODE_NAME}/proxy/configz" | jq '.kubeletconfig|.kind="KubeletConfiguration"|.apiVersion="kubelet.config.k8s.io/v1beta1"' > kubelet_configz_${NODE_NAME}
```
Note that we have to manually add the `kind` and `apiVersion` to the downloaded
object, as these are not reported by the configz endpoint. This is one of the
limitations of the endpoint.
{{< note >}}
You need to manually add the `kind` and `apiVersion` to the downloaded
object, because they are not reported by the `configz` endpoint.
{{< /note >}}
### Edit the configuration file
#### Edit the configuration file
Using your editor of choice, change one of the parameters in the
`kubelet_configz_${NODE_NAME}` file from the previous step. A QPS parameter,
`eventRecordQPS` for example, is a good candidate.
Using a text editor, change one of the parameters in the
file generated by the previous procedure. For example, you
might edit the QPS parameter `eventRecordQPS`.
### Push the configuration file to the control plane
#### Push the configuration file to the control plane
Push the edited configuration file to the control plane with the
following command:
```
$ kubectl -n kube-system create configmap my-node-config --from-file=kubelet=kubelet_configz_${NODE_NAME} --append-hash -o yaml
```bash
kubectl -n kube-system create configmap my-node-config --from-file=kubelet=kubelet_configz_${NODE_NAME} --append-hash -o yaml
```
You should see a response similar to:
This is an example of a valid response:
```
```none
apiVersion: v1
data:
kubelet: |
@@ -154,304 +161,204 @@ metadata:
uid: 946d785e-998a-11e7-a8dd-42010a800006
```
Note that the configuration data must appear under the ConfigMap's
`kubelet` key.
We create the ConfigMap in the `kube-system` namespace, which is appropriate
because this ConfigMap configures a Kubernetes system component - the Kubelet.
The ConfigMap is created in the `kube-system` namespace because this
ConfigMap configures a Kubelet, which is Kubernetes system component.
The `--append-hash` option appends a short checksum of the ConfigMap contents
to the name. This is convenient for an edit->push workflow, as it will
automatically, yet deterministically, generate new names for new ConfigMaps.
to the name. This is convenient for an edit-then-push workflow, because it
automatically, yet deterministically, generates new names for new ConfigMaps.
The name that includes this generated hash is referred to as `CONFIG_MAP_NAME`
in the following examples.
We use the `-o yaml` output format so that the name, namespace, and uid are all
reported following creation. We will need these in the next step. We will refer
to the name as CONFIG_MAP_NAME and the uid as CONFIG_MAP_UID.
### Authorize your Node to read the new ConfigMap
Now that you've created a new ConfigMap, you need to authorize your node to
read it. First, create a Role for your new ConfigMap with the
following commands:
```
$ export CONFIG_MAP_NAME=name-from-previous-output
$ kubectl -n kube-system create role ${CONFIG_MAP_NAME}-reader --verb=get --resource=configmap --resource-name=${CONFIG_MAP_NAME}
```
Next, create a RoleBinding to associate your Node with the new Role:
```
$ kubectl -n kube-system create rolebinding ${CONFIG_MAP_NAME}-reader --role=${CONFIG_MAP_NAME}-reader --user=system:node:${NODE_NAME}
```
Once the Node Authorizer is updated to do this automatically, you will
be able to skip this step.
### Set the Node to use the new configuration
#### Set the Node to use the new configuration
Edit the Node's reference to point to the new ConfigMap with the
following command:
```
```bash
kubectl edit node ${NODE_NAME}
```
Once in your editor, add the following YAML under `spec`:
In your text editor, add the following YAML under `spec`:
```
```yaml
configSource:
configMapRef:
configMap:
name: CONFIG_MAP_NAME
namespace: kube-system
uid: CONFIG_MAP_UID
kubeletConfigKey: kubelet
```
Be sure to specify all three of `name`, `namespace`, and `uid`.
You must specify all three of `name`, `namespace`, and `kubeletConfigKey`.
The `kubeletConfigKey` parameter shows the Kubelet which key of the ConfigMap
contains its config.
### Observe that the Node begins using the new configuration
#### Observe that the Node begins using the new configuration
Retrieve the Node with `kubectl get node ${NODE_NAME} -o yaml`, and look for the
`KubeletConfigOK` condition in `status.conditions`. You should see the message
`Using current (UID: CONFIG_MAP_UID)` when the Kubelet starts using the new
configuration.
Retrieve the Node using the `kubectl get node ${NODE_NAME} -o yaml` command and inspect
`Node.Status.Config`. The config sources corresponding to the `active`,
`assigned`, and `lastKnownGood` configurations are reported in the status.
For convenience, you can use the following command (using `jq`) to filter down
to the `KubeletConfigOK` condition:
- The `active` configuration is the version the Kubelet is currently running with.
- The `assigned` configuration is the latest version the Kubelet has resolved based on
`Node.Spec.ConfigSource`.
- The `lastKnownGood` configuration is the version the
Kubelet will fall back to if an invalid config is assigned in `Node.Spec.ConfigSource`.
The`lastKnownGood` configuration might not be present if it is set to its default value,
the local config deployed with the node. The status will update `lastKnownGood` to
match a valid `assigned` config after the Kubelet becomes comfortable with the config.
The details of how the Kubelet determines a config should become the `lastKnownGood` are
not guaranteed by the API, but is currently implemented as a 10-minute grace period.
You can use the following command (using `jq`) to filter down
to the config status:
```bash
kubectl get no ${NODE_NAME} -o json | jq '.status.config'
```
$ kubectl get no ${NODE_NAME} -o json | jq '.status.conditions|map(select(.type=="KubeletConfigOK"))'
[
{
"lastHeartbeatTime": "2017-09-20T18:08:29Z",
"lastTransitionTime": "2017-09-20T18:08:17Z",
"message": "using current: /api/v1/namespaces/kube-system/configmaps/my-node-config-gkt4c2m4b2",
"reason": "passing all checks",
"status": "True",
"type": "KubeletConfigOK"
The following is an example response:
```json
{
"active": {
"configMap": {
"kubeletConfigKey": "kubelet",
"name": "my-node-config-9mbkccg2cc",
"namespace": "kube-system",
"resourceVersion": "1326",
"uid": "705ab4f5-6393-11e8-b7cc-42010a800002"
}
},
"assigned": {
"configMap": {
"kubeletConfigKey": "kubelet",
"name": "my-node-config-9mbkccg2cc",
"namespace": "kube-system",
"resourceVersion": "1326",
"uid": "705ab4f5-6393-11e8-b7cc-42010a800002"
}
},
"lastKnownGood": {
"configMap": {
"kubeletConfigKey": "kubelet",
"name": "my-node-config-9mbkccg2cc",
"namespace": "kube-system",
"resourceVersion": "1326",
"uid": "705ab4f5-6393-11e8-b7cc-42010a800002"
}
}
]
```
If something goes wrong, you may see one of several different error conditions,
detailed in the table of KubeletConfigOK conditions, below. When this happens, you
should check the Kubelet's log for more details.
### Edit the configuration file again
To change the configuration again, we simply repeat the above workflow.
Try editing the `kubelet` file, changing the previously changed parameter to a
new value.
### Push the newly edited configuration to the control plane
Push the new configuration to the control plane in a new ConfigMap with the
following command:
}
```
$ kubectl create configmap my-node-config --namespace=kube-system --from-file=kubelet=kubelet_configz_${NODE_NAME} --append-hash -o yaml
```
This new ConfigMap will get a new name, as we have changed the contents.
We will refer to the new name as NEW_CONFIG_MAP_NAME and the new uid
as NEW_CONFIG_MAP_UID.
If an error occurs, the Kubelet reports it in the `Node.Status.Config.Error`
structure. Possible errors are listed in
[Understanding Node.Status.Config.Error messages](#understanding-node-status-config-error-messages).
You can search for the identical text in the Kubelet log for additional details
and context about the error.
### Authorize your Node to read the new ConfigMap
#### Make more changes
Now that you've created a new ConfigMap, you need to authorize your node to
read it. First, create a Role for your new ConfigMap with the
following commands:
Follow the workflow above to make more changes and push them again. Each time
you push a ConfigMap with new contents, the --append-hash kubectl option creates
the ConfigMap with a new name. The safest rollout strategy is to first create a
new ConfigMap, and then update the Node to use the new ConfigMap.
```
$ export NEW_CONFIG_MAP_NAME=name-from-previous-output
$ kubectl -n kube-system create role ${NEW_CONFIG_MAP_NAME}-reader --verb=get --resource=configmap --resource-name=${NEW_CONFIG_MAP_NAME}
```
#### Reset the Node to use its local default configuration
Next, create a RoleBinding to associate your Node with the new Role:
To reset the Node to use the configuration it was provisioned with, edit the
Node using `kubectl edit node ${NODE_NAME}` and remove the
`Node.Spec.ConfigSource` field.
```
$ kubectl -n kube-system create rolebinding ${NEW_CONFIG_MAP_NAME}-reader --role=${NEW_CONFIG_MAP_NAME}-reader --user=system:node:${NODE_NAME}
```
#### Observe that the Node is using its local default configuration
Once the Node Authorizer is updated to do this automatically, you will
be able to skip this step.
### Configure the Node to use the new configuration
Once more, edit the Node's `spec.configSource` with
`kubectl edit node ${NODE_NAME}`. Your new `spec.configSource` should look like
the following, with `name` and `uid` substituted as necessary:
```
configSource:
configMapRef:
name: ${NEW_CONFIG_MAP_NAME}
namespace: kube-system
uid: ${NEW_CONFIG_MAP_UID}
```
### Observe that the Kubelet is using the new configuration
Once more, retrieve the Node with `kubectl get node ${NODE_NAME} -o yaml`, and
look for the `KubeletConfigOK` condition in `status.conditions`. You should see the message
`using current: /api/v1/namespaces/kube-system/configmaps/${NEW_CONFIG_MAP_NAME}` when the Kubelet starts using the
new configuration.
### Deauthorize your Node from reading the old ConfigMap
Once you know your Node is using the new configuration and are confident that
the new configuration has not caused any problems, it is a good idea to
deauthorize the node from reading the old ConfigMap. Run the following
commands to remove the RoleBinding and Role:
```
$ kubectl -n kube-system delete rolebinding ${CONFIG_MAP_NAME}-reader
$ kubectl -n kube-system delete role ${CONFIG_MAP_NAME}-reader
```
Note that this does not necessarily prevent the Node from reverting to the old
configuration, as it may locally cache the old ConfigMap for an indefinite
period of time.
You may optionally also choose to remove the old ConfigMap:
```
$ kubectl -n kube-system delete configmap ${CONFIG_MAP_NAME}
```
Once the Node Authorizer is updated to do this automatically, you will
be able to skip this step.
### Reset the Node to use its local default configuration
Finally, if you wish to reset the Node to use the configuration it was
provisioned with, simply edit the Node with `kubectl edit node ${NODE_NAME}` and
remove the `spec.configSource` subfield.
### Observe that the Node is using its local default configuration
After removing this subfield, you should eventually observe that the KubeletConfigOK
condition's message reverts to `using current: local`.
### Deauthorize your Node from reading the old ConfigMap
Once you know your Node is using the default configuration again, it is a good
idea to deauthorize the node from reading the old ConfigMap. Run the following
commands to remove the RoleBinding and Role:
```
$ kubectl -n kube-system delete rolebinding ${NEW_CONFIG_MAP_NAME}-reader
$ kubectl -n kube-system delete role ${NEW_CONFIG_MAP_NAME}-reader
```
Note that this does not necessarily prevent the Node from reverting to the old
ConfigMap, as it may locally cache the old ConfigMap for an indefinite
period of time.
You may optionally also choose to remove the old ConfigMap:
```
$ kubectl -n kube-system delete configmap ${NEW_CONFIG_MAP_NAME}
```
Once the Node Authorizer is updated to do this automatically, you will
be able to skip this step.
After removing this subfield, `Node.Status.Config` eventually becomes
empty, since all config sources have been reset to `nil`, which indicates that
the local default config is `assigned`, `active`, and `lastKnownGood`, and no
error is reported.
{{% /capture %}}
{{% capture discussion %}}
## Kubectl Patch Example
As mentioned above, there are many ways to change a Node's configSource.
Here is an example command that uses `kubectl patch`:
```
kubectl patch node ${NODE_NAME} -p "{\"spec\":{\"configSource\":{\"configMapRef\":{\"name\":\"${CONFIG_MAP_NAME}\",\"namespace\":\"kube-system\",\"uid\":\"${CONFIG_MAP_UID}\"}}}}"
You can change a Node's configSource using several different mechanisms.
This example uses `kubectl patch`:
```bash
kubectl patch node ${NODE_NAME} -p "{\"spec\":{\"configSource\":{\"configMap\":{\"name\":\"${CONFIG_MAP_NAME}\",\"namespace\":\"kube-system\",\"kubeletConfigKey\":\"kubelet\"}}}}"
```
## Understanding KubeletConfigOK Conditions
## Understanding how the Kubelet checkpoints config
The following table describes several of the `KubeletConfigOK` Node conditions you
might encounter in a cluster that has Dynamic Kubelet Config enabled. If you
observe a condition with `status=False`, you should check the Kubelet log for
more error details by searching for the message or reason text.
When a new config is assigned to the Node, the Kubelet downloads and unpacks the
config payload as a set of files on the local disk. The Kubelet also records metadata
that locally tracks the assigned and last-known-good config sources, so that the
Kubelet knows which config to use across restarts, even if the API server becomes
unavailable. After checkpointing a config and the relevant metadata, the Kubelet
exits if it detects that the assigned config has changed. When the Kubelet is
restarted by the OS-level service manager (such as `systemd`), it reads the new
metadata and uses the new config.
The recorded metadata is fully resolved, meaning that it contains all necessary
information to choose a specific config version - typically a `UID` and `ResourceVersion`.
This is in contrast to `Node.Spec.ConfigSource`, where the intended config is declared
via the idempotent `namespace/name` that identifies the target ConfigMap; the Kubelet
tries to use the latest version of this ConfigMap.
When you are debugging problems on a node, you can inspect the Kubelet's config
metadata and checkpoints. The structure of the Kubelet's checkpointing directory is:
```none
- --dynamic-config-dir (root for managing dynamic config)
| - meta
| - assigned (encoded kubeletconfig/v1beta1.SerializedNodeConfigSource object, indicating the assigned config)
| - last-known-good (encoded kubeletconfig/v1beta1.SerializedNodeConfigSource object, indicating the last-known-good config)
| - checkpoints
| - uid1 (dir for versions of object identified by uid1)
| - resourceVersion1 (dir for unpacked files from resourceVersion1 of object with uid1)
| - ...
| - ...
```
## Understanding Node.Status.Config.Error messages
The following table describes error messages that can occur
when using Dynamic Kubelet Config. You can search for the identical text
in the Kubelet log for additional details and context about the error.
<table>
<table align="left">
<tr>
<th>Possible Messages</th>
<th>Possible Reasons</th>
<th>Status</th>
<th>Error Message</th>
<th>Possible Causes</th>
</tr>
<tr>
<td><p>using current: local</p></td>
<td><p>when the config source is nil, the Kubelet uses its local config</p></td>
<td><p>True</p></td>
<td><p>failed to load config, see Kubelet log for details</p></td>
<td><p>The Kubelet likely could not parse the downloaded config payload, or encountered a filesystem error attempting to load the payload from disk.</p></td>
</tr>
<tr>
<td><p>using current: /api/v1/namespaces/${CURRENT_CONFIG_MAP_NAMESPACE}/configmaps/${CURRENT_CONFIG_MAP_NAME}</p></td>
<td><p>passing all checks</p></td>
<td><p>True</p></td>
<td><p>failed to validate config, see Kubelet log for details</p></td>
<td><p>The configuration in the payload, combined with any command-line flag overrides, and the sum of feature gates from flags, the config file, and the remote payload, was determined to be invalid by the Kubelet.</p></td>
</tr>
<tr>
<td><p>using last-known-good: local</p></td>
<td>
<ul>
<li>failed to load current: /api/v1/namespaces/${CURRENT_CONFIG_MAP_NAMESPACE}/configmaps/${CURRENT_CONFIG_MAP_NAME}</li>
<li>failed to parse current: /api/v1/namespaces/${CURRENT_CONFIG_MAP_NAMESPACE}/configmaps/${CURRENT_CONFIG_MAP_NAME}</li>
<li>failed to validate current: /api/v1/namespaces/${CURRENT_CONFIG_MAP_NAMESPACE}/configmaps/${CURRENT_CONFIG_MAP_NAME}</li>
</ul>
</td>
<td><p>False</p></td>
<td><p>invalid NodeConfigSource, exactly one subfield must be non-nil, but all were nil</p></td>
<td><p>Since Node.Spec.ConfigSource is validated by the API server to contain at least one non-nil subfield, this likely means that the Kubelet is older than the API server and does not recognize a newer source type.</p></td>
</tr>
<tr>
<td><p>using last-known-good: /api/v1/namespaces/${LAST_KNOWN_GOOD_CONFIG_MAP_NAMESPACE}/configmaps/${LAST_KNOWN_GOOD_CONFIG_MAP_NAME}</p></td>
<td>
<ul>
<li>failed to load current: /api/v1/namespaces/${CURRENT_CONFIG_MAP_NAMESPACE}/configmaps/${CURRENT_CONFIG_MAP_NAME}</li>
<li>failed to parse current: /api/v1/namespaces/${CURRENT_CONFIG_MAP_NAMESPACE}/configmaps/${CURRENT_CONFIG_MAP_NAME}</li>
<li>failed to validate current: /api/v1/namespaces/${CURRENT_CONFIG_MAP_NAMESPACE}/configmaps/${CURRENT_CONFIG_MAP_NAME}</li>
</ul>
</td>
<td><p>False</p></td>
<td><p>failed to sync: failed to download config, see Kubelet log for details</p></td>
<td><p>The Kubelet could not download the config. It is possible that Node.Spec.ConfigSource could not be resolved to a concrete API object, or that network errors disrupted the download attempt. The Kubelet will retry the download when in this error state.</p></td>
</tr>
<tr>
<td>
<p>
The reasons in the next column could potentially appear for any of
the above messages.
</p>
<p>
This condition indicates that the Kubelet is having trouble
reconciling `spec.configSource`, and thus no change to the in-use
configuration has occurred.
</p>
<p>
The "failed to sync" reasons are specific to the failure that
occurred, and the next column does not necessarily contain all
possible failure reasons.
</p>
</td>
<td>
<p>failed to sync, reason:</p>
<ul>
<li>failed to read Node from informer object cache</li>
<li>failed to reset to local config</li>
<li>invalid NodeConfigSource, exactly one subfield must be non-nil, but all were nil</li>
<li>invalid ObjectReference, all of UID, Name, and Namespace must be specified</li>
<li>invalid ConfigSource.ConfigMapRef.UID: ${UID} does not match ${API_PATH}.UID: ${UID_OF_CONFIG_MAP_AT_API_PATH}</li>
<li>failed to determine whether object ${API_PATH} with UID ${UID} was already checkpointed</li>
<li>failed to download ConfigMap with name ${NAME} from namespace ${NAMESPACE}</li>
<li>failed to save config checkpoint for object ${API_PATH} with UID ${UID}</li>
<li>failed to set current config checkpoint to local config</li>
<li>failed to set current config checkpoint to object ${API_PATH} with UID ${UID}</li>
</ul>
</td>
<td><p>False</p></td>
<td><p>failed to sync: internal failure, see Kubelet log for details</p></td>
<td><p>The Kubelet encountered some internal problem and failed to update its config as a result. Examples include filesystem errors and reading objects from the internal informer cache.</p></td>
</tr>
<tr>
<td><p>internal failure, see Kubelet log for details</p></td>
<td><p>The Kubelet encountered some internal problem while manipulating config, outside of the configuration sync loop.</p></td>
</tr>
</table>
{{% /capture %}}