Kubernetes: Difference between revisions
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In addition to standard Kubernetes objects, '''operators''' watch for and allow you to instantiate custom resources (CR). | In addition to standard Kubernetes objects, '''operators''' watch for and allow you to instantiate custom resources (CR). | ||
==Administration== | ==Kubeadm Administration== | ||
Notes on administering kubernetes clusters. | Notes on administering kubernetes clusters. | ||
Kuberenetes has many parts and administration is very tedious which is why K3S exists. I'd recommend against using kubeadm for a homelab. | |||
===Installation=== | ===Installation=== | ||
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To renew the certificates manually, run <code>kubeadm certs renew all</code> and restart your control plane services. | To renew the certificates manually, run <code>kubeadm certs renew all</code> and restart your control plane services. | ||
Note that if you lets the certificates expire, you will need to setup kubectl again. | Note that if you lets the certificates expire, you will need to setup kubectl again. | ||
Issues connecting with etcd | |||
I ran into this when trying to kubeadm upgrade | |||
;context deadline exceeded remote error: tls: bad certificate | |||
Kubeadm stores etcd certificates in <code>/etc/kubernetes/pki/etcd/</code>. | |||
Follow this to generate new certificates: https://github.com/etcd-io/etcd/issues/9785#issuecomment-432438748 | |||
You will need to create a temporary files for ca-config.json and server.json to generate new keys. | |||
Make sure in the server.json to set the key algo to "rsa" and size to 2048. In the same file, set your CN to 127.0.0.1 and the hosts to [127.0.0.1, your local IP]. | |||
;cannot validate certificate for 127.0.0.1 because it doesn't contain any IP SANs | |||
This means your hosts in server.json is not correct when you generated the new keys. | |||
===Pods per node=== | ===Pods per node=== | ||
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You may increase this up to a limit of 255 with the default networking subnet.<br> | You may increase this up to a limit of 255 with the default networking subnet.<br> | ||
For reference, GCP GKE uses 110 pods per node and AWS EKS uses 250 pods per node. | For reference, GCP GKE uses 110 pods per node and AWS EKS uses 250 pods per node. | ||
===Changing Master Address=== | |||
See https://ystatit.medium.com/how-to-change-kubernetes-kube-apiserver-ip-address-402d6ddb8aa2 | |||
==kubectl== | ==kubectl== | ||
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==KubeVirt== | ==KubeVirt== | ||
{{main | KubeVirt}} | {{main | KubeVirt}} | ||
KubeVirt allows you to run virtual machines | KubeVirt allows you to run virtual machines on your Kubernetes cluster. | ||
==Resources== | ==Resources== | ||