forked from rook/rook
Alexander Trost
c7afa0eb43
This is the first phase miscellaneous part of three phases to improve and rework the Rook documentation for better user accessibility to the Rook projects and with that the storage providers. Phase two is about automatic generation of CRD documentation and phase three is about reworking the docs themselves and, e.g., examples for CRDs and certain use cases. Signed-off-by: Alexander Trost <galexrt@googlemail.com>
91 lines
4.0 KiB
Markdown
91 lines
4.0 KiB
Markdown
---
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title: Container Linux
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weight: 11500
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indent: true
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---
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# Using the Container Linux Update Operator with Rook
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When you are using Container Linux (CoreOS) and have the update engine enabled, it could be that a node reboots quickly after another not leaving enough time for the Rook cluster to rebuild. The [Container Linux Update Operator](https://github.com/coreos/container-linux-update-operator) is the solution for this, you can block your nodes to reboot until the Ceph cluster is healthy.
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## Prerequisites
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* An operational Container Linux Kubernetes cluster (Successfully tested with 1.8.4)
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* A working rook cluster
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* The update-engine.service systemd unit on each machine should be unmasked, enabled and started in systemd
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* The locksmithd.service systemd unit on each machine should be masked and stopped in systemd
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## Start the update operator
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Proper reading of the README on the [Container Linux Update Operator](https://github.com/coreos/container-linux-update-operator) is necessary. Clone the repo and go in the `examples` directory.
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Look for the file named `update-operator.yaml` and update the `command` part of the container from:
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```yaml
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command:
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- "/bin/update-operator"
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```
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to:
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```yaml
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command:
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- "/bin/update-operator"
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- "--before-reboot-annotations"
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- "ceph-before-reboot-check"
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- "--after-reboot-annotations"
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- "ceph-after-reboot-check"
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```
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You can also add the `-v 6` argument for more extensive logging.
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Now create the update-operator by invoking following commands:
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```console
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kubectl create -f namespace.yaml
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kubectl create -f cluster-role.yaml
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kubectl create -f cluster-role-binding.yaml
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kubectl create -f update-operator.yaml
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kubectl create -f update-agent.yaml
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```
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These files create a new namespace `reboot-coordinator`, configured to listen for the node annotation `ceph-reboot-check`. Now you can create both files in the `cluster/examples/coreos` folder, here's a short description of what each file does:
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* `rbac.yaml`: This file contains the necessary RBAC settings.
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* `ceph-after-reboot-script.yaml`: This file creates a `ConfigMap` containing a bash script which will be mounted in the `rook-toolbox` image as executable file.
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* `ceph-before-reboot-script.yaml`: This file creates a `ConfigMap` containing a bash script which will be mounted in the `rook-toolbox` image as executable file.
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* `before-reboot-daemonset.yaml`: This file creates a `DaemonSet` which waits for a node being labeled `before-reboot=true`, runs and checks the Ceph status. If all is correct, it annotates the node with `ceph-before-reboot-check=true`.
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* `after-reboot-daemonset.yaml`: This file creates a `DaemonSet` which waits for a node being labeled `after-reboot=true`, runs and unsets the `noout` option for the ceph OSDs. If all is correct, it annotates the node with `ceph-after-reboot-check=true`.
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The node annotation `ceph-no-noout=true` can be used to avoid `ceph-before-reboot-check` from setting the OSD `noout` flag. This annotation should only be used when deleting a node from a cluster, this way the cluster starts rebalancing immediately, not waiting for the node to come back up.
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```console
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kubectl create -f rbac.yaml
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kubectl create -f ceph-after-reboot-script.yaml
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kubectl create -f ceph-before-reboot-script.yaml
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kubectl create -f before-reboot-daemonset.yaml
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kubectl create -f after-reboot-daemonset.yaml
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```
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## Destroy the update operator
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To destroy all elements created in this file, run:
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```console
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kubectl delete -f before-reboot-daemonset.yaml
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kubectl delete -f after-reboot-daemonset.yaml
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kubectl delete -f ceph-after-reboot-script.yaml
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kubectl delete -f ceph-before-reboot-script.yaml
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kubectl delete -f rbac.yaml
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```
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Then you may safely delete the update operator itself:
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From the directory of the Container Linux Update Operator you cloned earlier, go again into the `examples` folder and run following commands:
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```console
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kubectl delete -f update-agent.yaml
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kubectl delete -f update-operator.yaml
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kubectl delete -f cluster-role-binding.yaml
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kubectl delete -f cluster-role.yaml
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kubectl delete -f namespace.yaml
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```
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