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| Code Block |
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| language | bash |
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| title | Update in progress... |
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| collapse | true |
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$ watch -x kubectl get pod,node -o wide -A
#
NAMESPACE The following screen will appear, which updatesNAME periodically
Every 2.0s: kubectl get pod,node -o wide -A READY STATUS node1: TueRESTARTS Mar 9 17:18:01 2021
NAMESPACE NAMEAGE IP NODE NOMINATED NODE READINESS GATES
ingress-nginx pod/ingress-nginx-controller-d6vp7 READY STATUS RESTARTS 1/1 AGE IPRunning 0 NODE
default 12d pod/netchecker-agent-hostnet-l6s5x 10.233.97.26 master1 <none> 1/1 Running 0 <none>
kube-system pod/calico-kube-controllers-744ccf69c7-rjwk2 25h 192.168.100.181/1 node1
default Running 0 pod/netchecker-agent-hostnet-rf5jl 1/15d21h 10.233.110.40 Running 0worker1 <none> 25h 192.168.100.23 node2<none>
defaultkube-system pod/netcheckercalico-agentnode-hostnet-sc5h74f8n7 1/1 Running 0 1/1 25h 192.168.100.25 Running node3
default 0 pod/netchecker-agent-kqsz7 12d 192.168.100.206 worker1 1/1 <none> Running 0 <none>
kube-system 25hpod/calico-node-6wkqb 10.233.90.3 node1
default pod/netchecker-agent-lp5pf 1/1 Running 1/10 Running 0 12d 25h 10192.233168.92100.294 worker3 node3
default <none> pod/netchecker-agent-z7vb5 <none>
kube-system pod/calico-node-9ptsg 1/1 Running 0 1/1 25h 10.233.96.2Running 0 node2
default pod/netchecker-server-f98789d55-xr6n9 12d 1/1 192.168.100.102 master2 Running <none> 2 24h<none>
kube-system 10.233.96.8 node2
kube-system pod/calico-kube-controllers-596bd759d5-x2zqcnode-b64qh 1/1 Running 0 24h 192.168.100.23 node2
kube-system pod/calico-node-772q21/1 Running 0 12d 1/1 192.168.100.190 Running worker2 0 <none> 25h 192.168.100.23 node2<none>
kube-system pod/calico-node-lnh5zlh7p2 1/1 Running 0 25h12d 192.168.100.2524 node3
kube-system master1 pod/calico-node-zcqjh <none> <none>
kube-system pod/coredns-645b46f4b6-w4v57 1/1 Running 0 1/1 25h Running 192.168.100.18 0 node1
kube-system pod/coredns-657959df74-7289c 5d21h 10.233.98.24 1/1 master2 <none> Running 0 <none>
kube-system 24h 10.233.96.7 node2
kube-system pod/coredns-657959df74-rtl2d645b46f4b6-zmqwk 1/1 Running 0 24h5d21h 10.233.9097.430 node1
kube-systemmaster1 pod/dns-autoscaler-b5c786945-brq6n<none> 1/1<none>
kube-system Runningpod/dns-autoscaler-7f7b458498-kv2k9 0 24h 1/1 10.233.90.5 Running node1
kube-system0 pod/kube-apiserver-node1 5d21h 10.233.97.28 master1 1/1 <none> Running 0 <none>
kube-system 25hpod/kube-apiserver-master1 192.168.100.18 node1
kube-system pod/kube-controller-manager-node1 1/1 Running 15 0 12d 25h 192.168.100.1824 node1
kube-systemmaster1 pod/kube-proxy-67lvh<none> <none>
kube-system pod/kube-apiserver-master2 1/1 Running 011 (36h ago) 12d 24h 192.168.100.18102 node1
kube-systemmaster2 pod/kube-proxy-whqwb<none> <none>
kube-system pod/kube-controller-manager-master1 1/1 Running 17 0 12d 24h 192.168.100.2524 master1 <none> node3
kube-system pod/kube-proxy-zs6kf <none>
kube-system pod/kube-controller-manager-master2 1/1 Running 014 (36h ago) 12d 24h 192.168.100.23102 master2 <none> node2<none>
kube-system pod/kube-scheduler-node1proxy-dtsjz 1/1 Running 0 25h5d21h 192.168.100.1894 node1
kube-systemworker3 pod/metrics-server-5cd75b7749-d2594<none> 2/2<none>
kube-system Runningpod/kube-proxy-ft984 0 24h 10.233.90.6 node1
kube-system pod/nginx-proxy-node2 1/1 Running 0 1/1 5d21h Running 192.168.100.206 0 worker1 <none> 25h 192.168.100.23 node2<none>
kube-system pod/nginxkube-proxy-node3hht9g 1/1 Running 0 25h5d21h 192.168.100.2524 node3
kube-system pod/nodelocaldns-hj5t8 master1 <none> <none>
kube-system pod/kube-proxy-nqbw5 1/1 Running 0 25h 192.168.100.18 node1
kube-system pod1/nodelocaldns-j7zvh1 Running 0 5d21h 1/1 192.168.100.102 Runningmaster2 0<none> 25h <none>
kube-system 192.168.100.23 node2
pod/kube-proxy-systemz6mzs pod/nodelocaldns-jqbx7 1/1 Running 0 25h5d21h 192.168.100.25190 worker2 node3
NAMESPACE <none> NAME STATUS<none>
kube-system ROLES pod/kube-scheduler-master1 AGE VERSION INTERNAL-IP 1/1 EXTERNAL-IP Running OS-IMAGE
12 (4d12h ago) 12d node/node1192.168.100.24 Readymaster1 <none> control-plane,master 25h v1.20.4 192.168.100.18 <none>
kube-system <none> pod/kube-scheduler-master2 CentOS Linux 8
node/node2 Ready 1/1 <none> Running 14 (36h ago) 25h 12d v1.20.4 192.168.100.23102 master2 <none> CentOS Linux 8<none>
kube-system pod/kubernetes-dashboard-5c5f5d4547-mxgmp node1/node31 Ready Running <none> 0 25h5d21h v110.20.4233.103.30 192.168.100.25worker2 <none> CentOS Linux 8 |
...
<none>
kube-system pod/kubernetes-metrics-scraper-756f68fffd-dqcmk 1/1 Running 0 5d21h 10.233.110.39 worker1 <none> <none>
kube-system pod/metrics-server-69d9447b96-td7z7 1/1 Running 0 5d21h 10.233.103.31 worker2 <none> <none>
kube-system pod/nginx-proxy-worker1 1/1 Running 0 12d 192.168.100.206 worker1 <none> <none>
kube-system pod/nginx-proxy-worker2 1/1 Running 0 12d 192.168.100.190 worker2 <none> <none>
kube-system pod/nginx-proxy-worker3 1/1 Running 0 12d 192.168.100.94 worker3 <none> <none>
kube-system pod/nodelocaldns-64678 1/1 Running 6 (9d ago) 12d 192.168.100.190 worker2 <none> <none>
kube-system pod/nodelocaldns-d6c5r 1/1 Running 0 12d 192.168.100.94 worker3 <none> <none>
kube-system pod/nodelocaldns-l6ms9 1/1 Running 2 (9d ago) 12d 192.168.100.102 master2 <none> <none>
kube-system pod/nodelocaldns-q2dm9 1/1 Running 1 (12d ago) 12d 192.168.100.206 worker1 <none> <none>
kube-system pod/nodelocaldns-r9m9q 1/1 Running 0 12d 192.168.100.24 master1 <none> <none>
NAMESPACE NAME STATUS ROLES AGE VERSION INTERNAL-IP EXTERNAL-IP OS-IMAGE KERNEL-VERSION CONTAINER-RUNTIME
node/master1 Ready control-plane,master 252d v1.26.5 192.168.100.24 <none> Rocky Linux 8.8 (Green Obsidian) 4.18.0-477.27.1.el8_8.x86_64 containerd://1.7.1
node/master2 Ready control-plane,master 252d v1.26.5 192.168.100.102 <none> Rocky Linux 8.8 (Green Obsidian) 4.18.0-477.27.1.el8_8.x86_64 containerd://1.7.1
node/worker1 Ready worker 252d v1.26.5 192.168.100.206 <none> Rocky Linux 8.8 (Green Obsidian) 4.18.0-477.27.1.el8_8.x86_64 containerd://1.7.1
node/worker2 Ready worker 252d v1.26.5 192.168.100.190 <none> Rocky Linux 8.8 (Green Obsidian) 4.18.0-477.27.1.el8_8.x86_64 containerd://1.7.1
node/worker3 Ready worker 252d v1.26.5 192.168.100.94 <none> Rocky Linux 8.8 (Green Obsidian) 4.18.0-477.27.1.el8_8.x86_64 containerd://1.7.1 |
The nodes are not updated at the same time, but in turn. The node being updated changes its STATUS to Ready, SchedulingDisabled. As long as it remains in this state, you will notice that all the Pods implemented on it are eliminated and moved to the other available nodes (i.e. the node is in Drain state). Once the update is finished, it will return to Ready and move on to the next node.
Ansible tags
There is a quick way to update only a single aspect of our cluster. Thanks to the tags, we can launch the playbook cluster.yml, which will only update a specific part of the configuration. Let's suppose we want to change the configuration of the ingress, present in the addons.yml file. We make our modification and then, instead of running the playbook upgrade-cluster.yml, we use the command
| Code Block |
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| language | bash |
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| title | Tags (example 1) |
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$ ansible-playbook cluster.yml --tags ingress-controller |
With the --skip-tags flag, instead, it is possible to skip processes. In this example, there is a command to filter and apply only DNS configuration tasks and skip everything else related to host OS configuration and downloading images of containers
| Code Block |
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| language | bash |
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| title | Tags (example 2) |
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$ ansible-playbook cluster.yml --tags preinstall,facts --skip-tags=download,bootstrap-os |
This significantly reduces processing times. The complete list of tags defined in the playbooks can be found here.
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Use --tags and --skip-tags wise and only if you're 100% sure what you're doing |
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