ワンライナーで導入できるというはずなのですが、さすがラズベリーパイは手間取らせてくれました。そして解決できていない。
環境
- RaspberryPi 4B（Ubuntu 20.04 LTS）
原因がわかった問題
ノードがいつまでもReadyにならない
インストールには成功し、nodesを参照するがNotReady
root@rasp2:~# kubectl get nodes NAME STATUS ROLES AGE VERSION rasp2 NotReady <none> 21m v1.20.2-34+c6851e88267786
WARNING: The memory cgroup is not enabled.
inspectの実行結果。cgroupsが設定されていないためノードがReadyにならない
root@rasp2:~# microk8s inspect Inspecting Certificates Inspecting services Service snap.microk8s.daemon-cluster-agent is running Service snap.microk8s.daemon-containerd is running Service snap.microk8s.daemon-apiserver is running Service snap.microk8s.daemon-apiserver-kicker is running Service snap.microk8s.daemon-control-plane-kicker is running Service snap.microk8s.daemon-proxy is running Service snap.microk8s.daemon-kubelet is running Service snap.microk8s.daemon-scheduler is running Service snap.microk8s.daemon-controller-manager is running Copy service arguments to the final report tarball Inspecting AppArmor configuration Gathering system information Copy processes list to the final report tarball Copy snap list to the final report tarball Copy VM name (or none) to the final report tarball Copy disk usage information to the final report tarball Copy memory usage information to the final report tarball Copy server uptime to the final report tarball Copy current linux distribution to the final report tarball Copy openSSL information to the final report tarball Copy network configuration to the final report tarball Inspecting kubernetes cluster Inspect kubernetes cluster Inspecting juju Inspect Juju Inspecting kubeflow Inspect Kubeflow WARNING: The memory cgroup is not enabled. The cluster may not be functioning properly. Please ensure cgroups are enabled See for example: https://microk8s.io/docs/install-alternatives#heading--arm Building the report tarball Report tarball is at /var/snap/microk8s/2049/inspection-report-20210322_010730.tar.gz
/boot/firmware/cmdline.txtに以下を追加
cgroup_enable=memory cgroup_memory=1
RaspberryPiではデフォルトでcgroupsが有効化されていないようです。
原因が不明な問題
microk8sのインストールに失敗する
Setup snap "core" (10862) security profiles
インストール時に以下のようなエラーメッセージが表示されてしまった。
root@rasp3:/proc# snap install microk8s --classic error: cannot perform the following tasks: - Setup snap "core" (10862) security profiles (cannot setup profiles for snap "core": cannot create host snap-confine apparmor configuration: cannot reload snap-confine apparmor profile: cannot load apparmor profiles: exit status 1 apparmor_parser output: Cache read/write disabled: interface file missing. (Kernel needs AppArmor 2.4 compatibility patch.) Warning: unable to find a suitable fs in /proc/mounts, is it mounted? Use --subdomainfs to override. )
apparmorを再起動したら解消しました。
root@rasp3:/proc# /etc/init.d/apparmor restart Restarting apparmor (via systemctl): apparmor.service.
Automatically connect eligible plugs and slots of snap "microk8s"
上の対応でエラーの内容が変化した。
root@rasp3:/proc# snap install microk8s --classic
Setup snap "microk8s" (2049) security profiles |
error: cannot perform the following tasks:
- Automatically connect eligible plugs and slots of snap "microk8s" (internal error: auto-connect of &{"microk8s:kubernetes-support" "snapd:kubernetes-support"} failed: snap "snapd" has no slot named "kubernetes-support")
snapdを再起動すると解消した。
root@rasp3:~# systemctl restart snapd root@rasp3:~# snap install microk8s --classic microk8s (1.20/stable) v1.20.2 from Canonical✓ installed
ノードがいつまで経っても開始されない
他のノードは以下のように自分自身をkubectl get nodesできるが...
root@rasp2:~# kubectl get nodes NAME STATUS ROLES AGE VERSION rasp2 NotReady <none> 21m v1.20.2-34+c6851e88267786
問題の起きているノードでは自分自身も取得できない。
root@rasp3:~# kubectl get nodes No resources found
inspectを行った結果Service snap.microk8s.daemon-kubelet is not runningが出力されていました。
root@rasp3:~# microk8s inspect Inspecting Certificates Inspecting services Service snap.microk8s.daemon-cluster-agent is running Service snap.microk8s.daemon-containerd is running Service snap.microk8s.daemon-apiserver is running Service snap.microk8s.daemon-apiserver-kicker is running Service snap.microk8s.daemon-control-plane-kicker is running Service snap.microk8s.daemon-proxy is running FAIL: Service snap.microk8s.daemon-kubelet is not running
kubeletの再起動を実施 -> 変化なし
microk8s.resetを実施 -> 変化なし
root@rasp3:~# microk8s.reset Disabling all addons. （省略） deployment.apps/calico-kube-controllers created serviceaccount/calico-kube-controllers created root@rasp3:~# root@rasp3:~# microk8s inspect Inspecting Certificates Inspecting services Service snap.microk8s.daemon-cluster-agent is running Service snap.microk8s.daemon-containerd is running Service snap.microk8s.daemon-apiserver is running Service snap.microk8s.daemon-apiserver-kicker is running Service snap.microk8s.daemon-control-plane-kicker is running Service snap.microk8s.daemon-proxy is running FAIL: Service snap.microk8s.daemon-kubelet is not running （省略）
一か八かノードの再起動を実施 -> 直った（？？？）
（裏でcgroupsの問題対処済み）
root@rasp3:~# sudo reboot Connection to 192.168.3.13 closed by remote host. Connection to 192.168.3.13 closed. root@rasp3:~# microk8s inspect Inspecting Certificates Inspecting services Service snap.microk8s.daemon-cluster-agent is running Service snap.microk8s.daemon-containerd is running Service snap.microk8s.daemon-apiserver is running Service snap.microk8s.daemon-apiserver-kicker is running Service snap.microk8s.daemon-control-plane-kicker is running Service snap.microk8s.daemon-proxy is running Service snap.microk8s.daemon-kubelet is running Service snap.microk8s.daemon-scheduler is running Service snap.microk8s.daemon-controller-manager is running Copy service arguments to the final report tarball Inspecting AppArmor configuration Gathering system information Copy processes list to the final report tarball Copy snap list to the final report tarball Copy VM name (or none) to the final report tarball Copy disk usage information to the final report tarball Copy memory usage information to the final report tarball Copy server uptime to the final report tarball Copy current linux distribution to the final report tarball Copy openSSL information to the final report tarball Copy network configuration to the final report tarball Inspecting kubernetes cluster Inspect kubernetes cluster Inspecting juju Inspect Juju Inspecting kubeflow Inspect Kubeflow Building the report tarball Report tarball is at /var/snap/microk8s/2049/inspection-report-20210322_125516.tar.gz root@rasp3:~# kubectl get nodes NAME STATUS ROLES AGE VERSION rasp3 NotReady <none> 13s v1.20.2-34+c6851e88267786 （数分経過） root@rasp3:~# kubectl get nodes NAME STATUS ROLES AGE VERSION rasp3 Ready <none> 2m41s v1.20.2-34+c6851e88267786
なぜ解決したか不明。バックグラウンドでGlusterFSのレプリケーションを行なっていたのでプロセスが重たかった？
終わりに
microk8s、セットアップ簡単なようで難しかったです。
リターンは大きいので徒労というわけでもないけど、なんとも言えない感じです。
