10.Kubernetes 安装 CoreDNS 和 Metrics-server 插件

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已于 2023-12-29 14:28:15 修改

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于 2023-12-29 14:24:57 首次发布

本文链接：https://blog.youkuaiyun.com/yxydde/article/details/135290200

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Kubernetes 除了网络插件以为，还有两个重要的插件，那就是 CoreDNS 和 Metrics-server

1、CoreDNS

Kubernetes使用定制的CoreDNS应用程序实现名称解析和服务发现功能

ansible_k8s]# ansible-playbook -i example/hosts.multi-node  10.coredns.yml 

PLAY [kube_client] ************************************************************************************************************

TASK [coredns : Prepare k8s install dirs] *************************************************************************************
ok: [localhost]

TASK [Create coredns.yaml] ****************************************************************************************************
ok: [localhost]

TASK [Copy coredns.yaml] ******************************************************************************************************
changed: [localhost]

TASK [deploy coredns.yaml] ****************************************************************************************************
ok: [localhost] => {
    "msg": "  kubectl apply -f /root/k8s-ansible/example/yaml/coredns.yaml  "
}

PLAY RECAP ********************************************************************************************************************
localhost                  : ok=4    changed=1    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   

ansible_k8s]# kubectl apply -f /root/k8s-ansible/example/yaml/coredns.yaml 
serviceaccount/coredns unchanged
clusterrole.rbac.authorization.k8s.io/system:coredns unchanged
clusterrolebinding.rbac.authorization.k8s.io/system:coredns unchanged
configmap/coredns unchanged
deployment.apps/coredns configured
service/kube-dns unchanged


ansible_k8s]# kubectl get po -A | grep coredns
NAMESPACE       NAME                                       READY   STATUS      RESTARTS         AGE
kube-system     coredns-6f46dbdb7b-7hzq4                   1/1     Running     7 (7m55s ago)    10d

2、Metrics-server

Metrics Server通过服务发现机制发现集群上的所有节点，而后自动采集每个节点上kubelet的CPU和内存使用状态，是集群级别资源利用率数据的聚合器。

ansible_k8s]# ansible-playbook -i example/hosts.multi-node  11.metrics-server.yml 

PLAY [kube_client] ************************************************************************************************************

TASK [metrics-server : Prepare k8s install dirs] ******************************************************************************
ok: [localhost]

TASK [metrics-server : Copy deploy yaml] **************************************************************************************
ok: [localhost]

TASK [create metrics-server-certs secret] *************************************************************************************
ok: [localhost] => {
    "msg": "  kubectl -n kube-system create secret generic metrics-server-certs --from-file=/root/k8s-ansible/example/pki/metrics-server/metrics-server-key.pem --from-file=/root/k8s-ansible/example/pki/metrics-server/metrics-server.pem  "
}

TASK [deploy metrics-server] **************************************************************************************************
ok: [localhost] => {
    "msg": "  kubectl apply -f /root/k8s-ansible/example/yaml/metrics-server.yaml  "
}

PLAY RECAP ********************************************************************************************************************
localhost                  : ok=4    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   


ansible_k8s]# kubectl -n kube-system create secret generic metrics-server-certs --from-file=/root/k8s-ansible/example/pki/metrics-server/metrics-server-key.pem --from-file=/root/k8s-ansible/example/pki/metrics-server/metrics-server.pem
secret/metrics-server-certs created

ansible_k8s]# kubectl apply -f /root/k8s-ansible/example/yaml/metrics-server.yaml
serviceaccount/metrics-server unchanged
clusterrole.rbac.authorization.k8s.io/system:aggregated-metrics-reader unchanged
clusterrole.rbac.authorization.k8s.io/system:metrics-server unchanged
rolebinding.rbac.authorization.k8s.io/metrics-server-auth-reader unchanged
clusterrolebinding.rbac.authorization.k8s.io/metrics-server:system:auth-delegator unchanged
clusterrolebinding.rbac.authorization.k8s.io/system:metrics-server unchanged
service/metrics-server unchanged
deployment.apps/metrics-server configured
apiservice.apiregistration.k8s.io/v1beta1.metrics.k8s.io unchanged

ansible_k8s]# kubectl get po -A | grep metrics
NAMESPACE       NAME                                       READY   STATUS      RESTARTS         AGE
kube-system     metrics-server-9644c5989-bmjxb             1/1     Running     8 (8m19s ago)    10d

# 部署成功以后即可查看 pod 或 节点的负载情况
ansible_k8s]# kubectl top po -A 
NAMESPACE       NAME                                       CPU(cores)   MEMORY(bytes)   
default         http-dump-67cd5cd748-jtwjw                 0m           8Mi             
default         http-dump-67cd5cd748-ml4dv                 0m           10Mi            
default         http-dump-67cd5cd748-rfnbc                 1m           12Mi            
default         kuard-b8496fc59-4ss66                      1m           9Mi             
default         kuard-b8496fc59-g8txs                      1m           9Mi             
default         kuard-b8496fc59-l8ncs                      0m           7Mi             
ingress-nginx   ingress-nginx-controller-6blvg             4m           261Mi           
ingress-nginx   ingress-nginx-controller-8k9bk             3m           261Mi           
ingress-nginx   ingress-nginx-controller-qp6kn             3m           261Mi           
kube-system     calico-kube-controllers-84c5fc758f-m4rvb   5m           25Mi            
kube-system     calico-node-7spmb                          44m          154Mi           
kube-system     calico-node-b8bsq                          48m          152Mi           
kube-system     calico-node-fjk6b                          38m          145Mi           
kube-system     calico-node-m8xll                          43m          140Mi           
kube-system     calico-node-pn2tj                          47m          151Mi           
kube-system     coredns-6f46dbdb7b-7hzq4                   2m           25Mi            
kube-system     kube-lb-rocky01.example.io                 1m           11Mi            
kube-system     kube-lb-rocky02.example.io                 1m           11Mi            
kube-system     kube-lb-rocky03.example.io                 1m           25Mi            
kube-system     kube-lb-rocky04.example.io                 5m           25Mi            
kube-system     kube-lb-rocky05.example.io                 1m           25Mi            
kube-system     metrics-server-9644c5989-bmjxb             6m           36Mi            
ansible_k8s]# kubectl top nodes
NAME                 CPU(cores)   CPU%   MEMORY(bytes)   MEMORY%   
rocky01.example.io   215m         3%     888Mi           6%        
rocky02.example.io   255m         4%     887Mi           6%        
rocky03.example.io   223m         1%     1037Mi          3%        
rocky04.example.io   245m         1%     1068Mi          3%        
rocky05.example.io   256m         1%     1084Mi          3%