Add task doc for alpha dynamic kubelet configuration #5523
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| uid: 946d785e-998a-11e7-a8dd-42010a800006 | ||
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| Note that the configuration must be in a file named `kubelet`, so that the data appears under the `kubelet` key of the ConfigMap. |
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better move this note to line 66 where the file was generated.
| ### Set the Node to use the new configuration | ||
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| Each Kubelet watches a configuration reference on its respective Node object. When this reference changes, the Kubelet downloads the new configuration and restarts to begin using it. Edit the Node's reference to point to the new ConfigMap with the following command: | ||
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"Each Kubelet watches a configuration reference on its respective Node object. When this reference changes, the Kubelet downloads the new configuration and restarts to begin using it."
Better move this to line 31 because it is part of the "basic workflow".
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Probably we are supposed to add some text about the |
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@tengqm yeah, we should mention it somewhere. I think a mention and a link to a separate doc would be most appropriate, as it is a separate (though related) feature. |
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I'll start a docs review now. |
| As of Kubernetes 1.8, the new [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. | ||
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| **Warning:** The organization of the Kubelet's configuration type is still considered alpha, and it is likely to be restructured with breaking changes before graduating from alpha. | ||
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Add this line:
{% include feature-state-alpha.md %}
Then you can probably delete the first of your two Warnings.
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Just include it right at the bottom?
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The second warning is worth leaving IMO, we don't want users to assume this implies all fields are safe to change without care.
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Put {% include feature-state-alpha.md %} right after {% capture overview %}. Yes, I think we should keep the second warning.
| The basic workflow for configuring a Kubelet in a live cluster is as follows: | ||
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| 1. Write a yaml or json configuration file containing the Kubelet's configuration. | ||
| 2. Wrap this file in a ConfigMap and save it to the Kubernetes control plane. |
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yaml -> YAML
json -> JSON
Same thing in a couple other places, I think.
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@mtaufen Just a couple of comments. |
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| **Warning:** The organization of the Kubelet's configuration type is still considered alpha, and it is likely to be restructured with breaking changes before graduating from alpha. | ||
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| **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. |
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graduating to beta would be more logical
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Some things, like the kubeletconfig API group, might graduate directly to GA in 1.9 (this would make sense, as the set of knobs in that group is representative of the already-GA flags API).
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Writing graduating to GA makes sense to me
| {% endcapture %} | ||
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| {% capture prerequisites %} | ||
| - A live Kubernetes cluster at version 1.8 or higher must be running, with the `DynamicKubeletConfig` feature gate enabled and the Kubelet's `--dynamic-config-dir` flag set to a writeable directory on the Node. |
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with all components of v1.8 or higher, right?
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Is --dynamic-config-dir something you have to set manually or is there a default?
Something like /var/lib/kubelet/configz would make sense to me personally...
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No default. Providing no location disables the feature, similar to why we removed --require-kubeconfig.
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Master and Kubelet >= v1.8, yes.
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| 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. | ||
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| ### Workaround: Add system:Nodes subject to the system:Node ClusterRoleBinding |
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Ouch 😅, didn't know about this. Basically makes this feature 10x harder to use for kubeadm clusters, where node authz is always enabled... (of course creating this binding would solve it there as well, but that's not good)
Can't you instead tell the user to create a binding per-node?
i.e. YAML for a Role that can access configmap X in ns Y bound to user system:node:<my-node>?
I would like that way more
@liggitt where are we regarding implementing this on the node authz side?
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Yeah this was a major facepalm for me, because @liggitt warned me about this and then I realized we hadn't done it when I was testing these docs...
Yeah I can switch to a per-node-configmap binding, even though it adds an extra step to every config change in the doc...
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I plan to add read access to the config map to the node authorizer the same release the field leaves alpha, so probably 1.9
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Can't argue with that :)
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| The Dynamic Kubelet Configuration feature allows you to provide an override for the entire configuration object, rather than a per-field overlay. This is a simpler model that makes it easier to trace the source of configuration values 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. | ||
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| In the future, the Kubelet will be bootstrapped from a file on disk, 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 hitting 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. There is ongoing work to improve the endpoint, and in the future this will be a less "dirty" operation. This trick also requires the `jq` command to be installed on your machine, for unpacking and editing the json response from the endpoint. |
| 3. Run the following command to download and unpack the configuration from the configz endpoint: | ||
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| ``` | ||
| curl http://localhost:8001/api/v1/proxy/Nodes/NODE_NAME/configz | jq '.kubeletconfig|.kind="KubeletConfiguration"|.apiVersion="kubeletconfig/v1alpha1"' > kubelet |
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nit: Nodes -> nodes, curl -> curl -sSL, NODE_NAME -> ${NODE_NAME}
call the file kubelet_configz_${NODE_NAME}
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| Once more, edit the Node's `spec.configSource` with `kubectl edit Node NODE_NAME`. Your new `spec.configSource` should look like the following, with names substituted as necessary: | ||
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| ``` |
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| The following table describes several of the `ConfigOK` 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. | ||
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| <table> |
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Why not use markdown tables? Would be much easier to review
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Newlines are significant in markdown tables, so any cell that contains a lot of text would have to be on the same line.
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| This document describes editing Nodes using `kubectl edit`. There are other ways to modify a Node's spec, including `kubectl patch`, for example, which facilitate scripted workflows. | ||
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| 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. |
| 2. Wrap this file in a ConfigMap and save it to the Kubernetes control plane. | ||
| 3. Update the Kubelet's correspoinding Node object to use this ConfigMap. | ||
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| Each Kubelet watches a configuration reference on its respective Node object. When this reference changes, the Kubelet downloads the new configuration and restarts to begin using it. |
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Put a big warning or note that you must use some kind of process management system (like: systemd) to make the kubelet restart on a config change for this to work
Just in case there someone that isn't...
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| ### Basic Workflow Overview | ||
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| The basic workflow for configuring a Kubelet in a live cluster is as follows: |
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Please clarify that this will override ALL CLI args as a note, right?
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Well, all parameters covered by the KubeletConfiguration struct, but yes those are totally overridden. Will clarify.
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Updated PTAL. |
| 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. | ||
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| ### Authorize your Node to read the new ConfigMap |
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@mtaufen, Just one more thing: The {% include feature-state-alpha.md %} should be immediately after {% capture overview %} |
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@steveperry-53 looks like Travis is timing out? @mtaufen Yeah, we've been having trouble with Travis all day. Sometimes it works, sometimes it times out. Usually if I just keep rebuilding, it eventually works. |
* GC now supports non-core resources * Add two examples about how to analysis audits of kube-apiserver (#4264) * Deprecate system:nodes binding * [1.8] StatefulSet `initialized` annotation is now ignored. * inits the kubeadm upgrade docs addresses /issues/4689 * adds kubeadm upgrade cmd to ToC addresses /issues/4689 * add workload placement docs * ScaleIO - document udpate for 1.8 * Add documentation on storageClass.mountOptions and PV.mountOptions (#5254) * Add documentation on storageClass.mountOptions and PV.mountOptions * convert notes into callouts * Add docs for CustomResource validation add info about supported fields * advanced audit beta features (#5300) * Update job workload doc with backoff failure policy (#5319) Add to the Jobs documentation how to use the new backoffLimit field that limit the number of Pod failure before considering the Job as failed. * Documented additional AWS Service annotations (#4864) * Add device plugin doc under concepts/cluster-administration. (#5261) * Add device plugin doc under concepts/cluster-administration. * Update device-plugins.md * Update device-plugins.md Add meta description. Fix typo. Change bare metal deployment to manual deployment. * Update device-plugins.md Fix typo again. * Update page.version. (#5341) * Add documentation on storageClass.reclaimPolicy (#5171) * [Advanced audit] use new herf for audit-api (#5349) This tag contains all the changes in v1beta1 version. Update it now. * Added documentation around creating the InitializerConfiguration for the persistent volume label controller in the cloud-controller-manager (#5255) * Documentation for kubectl plugins (#5294) * Documentation for kubectl plugins * Update kubectl-plugins.md * Update kubectl-plugins.md * Updated CPU manager docs to match implementation. (#5332) * Noted limitation of alpha static cpumanager. * Updated CPU manager docs to match implementation. - Removed references to CPU pressure node condition and evictions. - Added note about new --cpu-manager-reconcile-period flag. - Added note about node allocatable requirements for static policy. - Noted limitation of alpha static cpumanager. * Move cpu-manager task link to rsc mgmt section. * init containers annotation removed in 1.8 (#5390) * Add documentation for TaintNodesByCondition (#5352) * Add documentation for TaintNodesByCondition * Update nodes.md * Update taint-and-toleration.md * Update daemonset.md * Update nodes.md * Update taint-and-toleration.md * Update daemonset.md * Fix deployments (#5421) * Document extended resources and OIR deprecation. (#5399) * Document extended resources and OIR deprecation. * Updated extended resources doc per reviews. * reverts extra spacing in _data/tasks.yml * addresses `kubeadm upgrade` review comments Feedback from @chenopis, @luxas, and @steveperry-53 addressed with this commit * HugePages documentation (#5419) * Update cpu-management-policies.md (#5407) Fixed the bad link. Modified "cpu" to "CPU". Added more 'yaml' as supplement. * Update RBAC docs for v1 (#5445) * Add user docs for pod priority and preemption (#5328) * Add user docs for pod priority and preemption * Update pod-priority-preemption.md * More updates * Update docs/admin/kubeadm.md for 1.8 (#5440) - Made a couple of minor wording changes (not strictly 1.8 related). - Did some reformatting (not strictly 1.8 related). - Updated references to the default token TTL (was infinite, now 24 hours). - Documented the new `--discovery-token-ca-cert-hash` and `--discovery-token-unsafe-skip-ca-verification` flags for `kubeadm join`. - Added references to the new `--discovery-token-ca-cert-hash` flag in all the default examples. - Added a new _Security model_ section that describes the security tradeoffs of the various discovery modes. - Documented the new `--groups` flag for `kubeadm token create`. - Added a note of caution under _Automating kubeadm_ that references the _Security model_ section. - Updated the component version table to drop 1.6 and add 1.8. - Update `_data/reference.yml` to try to get the sidebar fixed up and more consistent with `kubefed`. * Update StatefulSet Basics for 1.8 release (#5398) * addresses `kubeadm upgrade` review comments 2nd iteration review comments by @luxas * adds kubelet upgrade section to kubeadm upgrade * Fix a bulleted list on docs/admin/kubeadm.md. (#5458) I updated this doc yesterday and I was absolutely sure I fixed this, but I just saw that this commit got lost somehow. This was introduced recently in #5440. * Clarify the API to check for device plugins * Moving Flexvolume to separate out-of-tree section * addresses `kubeadm upgrade` review comments CC: @luxas * fixes kubeadm upgrade index * Update Stackdriver Logging documentation (#5495) * Re-update WordPress and MySQL PV doc to use apps/v1beta2 APIs (#5526) * Update statefulset concepts doc to use apps/v1beta2 APIs (#5420) * add document on kubectl's behavior regarding initializers (#5505) * Update docs/admin/kubeadm.md to cover self-hosting in 1.8. (#5497) This is a new beta feature in 1.8. * Update kubectl patch doc to use apps/v1beta2 APIs (#5422) * [1.8] Update "Run Applications" tasks to apps/v1beta2. (#5525) * Update replicated stateful application task for 1.8. * Update single instance stateful app task for 1.8. * Update stateless app task for 1.8. * Update kubectl patch task for 1.8. * fix the link of persistent storage (#5515) * update the admission-controllers.md index.md what-is-kubernetes.md link * fix the link of persistent storage * Add quota support for local ephemeral storage (#5493) * Add quota support for local ephemeral storage update the doc to this alpha feature * Update resource-quotas.md * Updated Deployments concepts doc (#5491) * Updated Deployments concepts doc * Addressed comments * Addressed more comments * Modify allocatable storage to ephemeral-storage (#5490) Update the doc to use ephemeral-storage instead of storage * Revamped concepts doc for ReplicaSet (#5463) * Revamped concepts doc for ReplicaSet * Minor changes to call out specific versions for selector defaulting and immutability * Addressed doc review comments * Remove petset documentations (#5395) * Update docs to use batch/v1beta1 cronjobs (#5475) * add federation job doc (#5485) * add federation job doc * Update job.md Edits for clarity and consistency * Update job.md Fixed a typo * update DaemonSet concept for 1.8 release (#5397) * update DaemonSet concept for 1.8 release * Update daemonset.md Fix typo. than -> then * Update bootstrap tokens doc for 1.8. (#5479) * Update bootstrap tokens doc for 1.8. This has some changes I missed when I was updating the main kubeadm documention: - Bootstrap tokens are now beta, not alpha (kubernetes/enhancements#130) - The apiserver flag to enable the authenticator changedin 1.8 (kubernetes/kubernetes#51198) - Added `auth-extra-groups` documentaion (kubernetes/kubernetes#50933) - Updated the _Token Management with `kubeadm`_ section to link to the main kubeadm docs, since it was just duplicated information. * Update bootstrap-tokens.md * Updated the Cassandra tutorial to use apps/v1beta2 (#5548) * add docs for AllowPrivilegeEscalation (#5448) Signed-off-by: Jess Frazelle <[email protected]> * Add local ephemeral storage alpha feature in managing compute resource (#5522) * Add local ephemeral storage alpha feature in managing compute resource Since 1.8, we add the local ephemeral storage alpha feature as one resource type to manage. Add this feature into the doc. * Update manage-compute-resources-container.md * Update manage-compute-resources-container.md * Update manage-compute-resources-container.md * Update manage-compute-resources-container.md * Update manage-compute-resources-container.md * Update manage-compute-resources-container.md * Added documentation for Metrics Server (#5560) * authorization: improve authorization debugging docs (#5549) * Document mount propagation (#5544) * Update /docs/setup/independent/create-cluster-kubeadm.md for 1.8. (#5524) This introduction needed a couple of small tweaks to cover the `--discovery-token-ca-cert-hash` flag added in kubernetes/kubernetes#49520 and some version bumps. * Add task doc for alpha dynamic kubelet configuration (#5523) * Fix input/output of selfsubjectaccess review (#5593) * Add docs for implementing resize (#5528) * Add docs for implementing resize * Update admission-controllers.md * Added link to PVC section * minor typo fixes * Update NetworkPolicy concept guide with egress and CIDR changes (#5529) * update zookeeper tutorial for 1.8 release * add doc for hostpath type (#5503) * Federated Hpa feature doc (#5487) * Federated Hpa feature doc * Federated Hpa feature doc review fixes * Update hpa.md * Update hpa.md * update cloud controller manager docs for v1.8 * Update cronjob with defaults information (#5556) * Kubernetes 1.8 reference docs (#5632) * Kubernetes 1.8 reference docs * Kubectl reference docs for 1.8 * Update side bar with 1.8 kubectl and api ref docs links * remove petset.md * update on state of HostAlias in 1.8 with hostNetwork Pod support (#5644) * Fix cron job deletion section (#5655) * update imported docs (#5656) * Add documentation for certificate rotation. (#5639) * Link to using kubeadm page * fix the command output fix the command output * fix typo in api/resources reference: "Worloads" * Add documentation for certificate rotation. * Create TOC entry for cloud controller manager. (#5662) * Updates for new versions of API types * Followup 5655: fix link to garbage collection (#5666) * Temporarily redirect resources-reference to api-reference. (#5668) * Update config for 1.8 release. (#5661) * Update config for 1.8 release. * Address reviewer comments. * Switch references in HPA docs from alpha to beta (#5671) The HPA docs still referenced the alpha version. This switches them to talk about v2beta1, which is the appropriate version for Kubernetes 1.8 * Deprecate openstack heat (#5670) * Fix typo in pod preset conflict example Move container port definition to the correct line. * Highlight openstack-heat provider deprecation The openstack-heat provider for kube-up is being deprecated and will be removed in a future release. * Temporarily fix broken links by redirecting. (#5672) * Fix broken links. (#5675) * Fix render of code block (#5674) * Fix broken links. (#5677) * Add a small note about auto-bootstrapped CSR ClusterRoles (#5660) * Update kubeadm install doc for v1.8 (#5676) * add draft workloads api content for 1.8 (#5650) * add draft workloads api content for 1.8 * edits per review, add tables, for 1.8 workloads api doc * fix typo * Minor fixes to kubeadm 1.8 upgrade guide. (#5678) - The kubelet upgrade instructions should be done on every host, not just worker nodes. - We should just upgrade all packages, instead of calling out kubelet specifically. This will also upgrade kubectl, kubeadm, and kubernetes-cni, if installed. - Draining nodes should also ignore daemonsets, and master errors can be ignored. - Make sure that the new kubeadm download is chmoded correctly. - Add a step to run `kubeadm version` to verify after downloading. - Manually approve new kubelet CSRs if rotation is enabled (known issue). * Release 1.8 (#5680) * Fix versions for 1.8 API ref docs * Updates for 1.8 kubectl reference docs * Kubeadm /docs/admin/kubeadm.md cleanup, editing. (#5681) * Update docs/admin/kubeadm.md (mostly 1.8 related). This is Fabrizio's work, which I'm committing along with my edits (in a commit on top of this). * A few of my own edits to clarify and clean up some Markdown.
| 1. Write a YAML or JSON configuration file containing the | ||
| Kubelet's configuration. | ||
| 2. Wrap this file in a ConfigMap and save it to the Kubernetes control plane. | ||
| 3. Update the Kubelet's correspoinding Node object to use this ConfigMap. |
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Thanks, sent typo fixes for the versions containing this doc:
- 1.10: Fix typo #7640
- 1.9: Fix typo #7641
- 1.8: Fix typo #7642
This documents how to change the Kubelet configuration on a single node in a live cluster with the new, alpha, Dynamic Kubelet Configuration feature.
/cc @luxas @dchen1107
This change is