Illustration of etcd access in kubernetes

Catalog

List of articles

Preface

One 、etcd What is it? ？

Two 、 Use steps

1. stay k8s Check the installed etcd

​2. Get into k8s Of etcd

3. Appoint etcd Version of 3​

4. View all nodes in the cluster （etcdctl member list）​

5. Write test data （etcdctl put /testdir/testkey "Hello world1"）

6. Read out the test data （etcdctl get /testdir/testkey）

​

summary

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Preface

Kubernetes Medium etcd visit .

Normal installation k8s, Didn't deliberately install etcd, utilize K8s Attached to etcd, Feel the etcd Read and write operations .

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Tips ： The following is the main body of this article , The following cases can be used for reference

One 、etcd What is it? ？

etcd It's a distributed one key-value Storage database .

Two 、 Use steps

1. stay k8s Check the installed etcd

kubectl get pod -n kube-system | grep etcd

2. Get into k8s Of etcd

kubectl exec -ti etcd-s205  -n kube-system  -- /bin/sh

etcd-s205 yes etcd Of pod Name ,

kube-system yes etcd In the namespace

 3. Appoint etcd Version of 3

export ETCDCTL_API=3

4. View all nodes in the cluster （etcdctl member list）

  The original order was etcdctl member list, Will make mistakes ,

"level":"warn","ts":"2022-01-23T07:20:36.684Z","caller":"clientv3/retry_interceptor.go:62","msg":"retrying of unary invoker failed","target":"endpoint://client-f4a0c47f-bfc5-4e20-938f-fd9f60be32fd/127.0.0.1:2379","attempt":0,"error":"rpc error: code = DeadlineExceeded desc = latest balancer error: all SubConns are in TransientFailure, latest connection error: connection closed"}
Error: context deadline exceeded

"level":"warn","ts":"2022-01-23T07:20:36.684Z","caller":"clientv3/retry_interceptor.go:62","msg":"retrying of unary invoker failed","target":"endpoint://client-f4a0c47f-bfc5-4e20-938f-fd9f60be32fd/127.0.0.1:2379","attempt":0,"error":"rpc error: code = DeadlineExceeded desc = latest balancer error: all SubConns are in TransientFailure, latest connection error: connection closed"}
Error: context deadline exceeded

To access with certificate parameters ,

Added certificate parameters

  --cacert=/etc/kubernetes/pki/etcd/ca.crt

  --cert=/etc/kubernetes/pki/etcd/healthcheck-client.crt

  --key=/etc/kubernetes/pki/etcd/healthcheck-client.key

etcdctl --cacert=/etc/kubernetes/pki/etcd/ca.crt --cert=/etc/kubernetes/pki/etcd/healthcheck-client.crt --key=/etc/kubernetes/pki/etcd/healthcheck-client.key member list

5. Write test data （etcdctl put /testdir/testkey "Hello world1"）

etcdctl --cacert=/etc/kubernetes/pki/etcd/ca.crt --cert=/etc/kubernetes/pki/etcd/healthcheck-client.crt --key=/etc/kubernetes/pki/etcd/healthcheck-client.key put /testdir/testkey "Hello world1"

6. Read out the test data （etcdctl get /testdir/testkey）

etcdctl --cacert=/etc/kubernetes/pki/etcd/ca.crt --cert=/etc/kubernetes/pki/etcd/healthcheck-client.crt --key=/etc/kubernetes/pki/etcd/healthcheck-client.key get /testdir/testkey

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summary

k8s Medium etcd, Add the certificate parameters , You can test and learn directly .