利用 Kubernetes DaemonSet 解决 DevOps-CD 流程中仓库自签证书分发问题

原理

DaemonSet方式启动Pod，将节点的/etc/docker/certs.d目录映射到Pod容器（类似于docker run -v）/a目录，保存有Docker仓库自签证书的ConfigMap以Volume方式挂载到Pod容器/b目录，通过K8S的LifeCycle控制器在Pod启动后将/b目录内容拷贝到/a目录，曲线完成Docker仓库自签名证书的分发。

说明

• 适用无主机登陆权限的K8S节点自签证书分发.
• ConfigMap名为docker-cacerts，可修改为其它名称，可存放多个仓库自签证书，对ConfigMap数据字段有一定要求：

Key1: Value1

Key2: Value2

  Key字段是“仓库地址_端口”模式，仓库地址可以是域名也可以是IP地址，端口为443的情况可以不带下划线和端口（视镜像tag决定Value为Docker仓库自签证书文本内容)

• DaemonSet与ConfigMap系Namespace级别资源，需注意资源Namespace归属
• ConfigMap更新后需Recreate对应Pod

步骤

1. 创建ConfigMap

以Harbor地址为https://10.50.32.35为例

$ obj_ns=deepexi
$ kubectl create configmap docker-cacerts --from-file=10.50.32.35=ca.crt -n ${obj_ns}
$ kubectl get configmap docker-cacerts -n ${obj_ns} --export
apiVersion: v1
data:
  ca.crt: |
    -----BEGIN CERTIFICATE-----
    MIIFrzCCA5egAwIBAgIJAIwAuuK+h8oIMA0GCSqGSIb3DQEBDQUAMG4xCzAJBgNV
    BAYTAkNOMRIwEAYDVQQIDAlHdWFuZ2RvbmcxEjAQBgNVBAcMCUd1YW5nemhvdTEQ
    MA4GA1UECgwHRGVlcGV4aTEPMA0GA1UECwwGRGV2b3BzMRQwEgYDVQQDDAtkZWVw
    ZXhpLnRvcDAeFw0yMDAzMTEwMjUzMTdaFw0zMDAzMDkwMjUzMTdaMG4xCzAJBgNV
    BAYTAkNOMRIwEAYDVQQIDAlHdWFuZ2RvbmcxEjAQBgNVBAcMCUd1YW5nemhvdTEQ
    MA4GA1UECgwHRGVlcGV4aTEPMA0GA1UECwwGRGV2b3BzMRQwEgYDVQQDDAtkZWVw
    ZXhpLnRvcDCCAiIwDQYJKoZIhvcNAQEBBQADggIPADCCAgoCggIBANv1RGx8fcv+
    gLIVe1RiVqLyuhDRhwaTMEBvdlL8t5K9e+V1PymAzNYz9eV3UN+Ud+0+XFfW6CCr
    8FLxquhSCBTv2l+cyCZ+2Cntnk9ViV58fSW7dvrdsORD93UdSqEPMX5YjL7otY4/
    D4KOyOvMycmk761bzOqrjqVGSnmkRFSB9wGxbi59irk2EohmtKqW8MGE9NTLIUud
    chGUujIqqOk7zIEFAeNbhZNFp8W/+gEtnybkt3w5YhpiGoTS7n1OJHitpp55yCGM
    c+qU2ph2OCGvjU9baSYsK2tX2QWTeKYw/Ls1KbFe5EtJ3iz6yd2KwUl+c/r5so+d
    oeAbI+mE1bVK5H6/N3TfuWoX4+kxdPtNIKMaQTKLVfbrwPZTUrO5PXaJNoFIGWw4
    PcKh8lDeB8mcApOPJDhsLyWbdbqDcJToWGh36HSI/A9gFuxdFHEM4d7Dp2nT2+sO
    x5/qHIyEoc3u5OEqBtt3HXxkisfTPEh9vhfjLfZTGwDMQcs+EULCR/q9xp94KzK5
    bVDsVSF4remDR8iAL+u0HAEjbfcCWuils1ph2TxIQ6cvdgqVK3+wzDkpl+xZhhsa
    Z9jCoOUZ7NB8q11kSmgFna6DXG4uiyO+nQwRAYrF8zU1vsbSAbGrz8nDqdRPory2
    gGSJJ5W4Nic81Hym4yuhCa7X+QqZSYgfAgMBAAGjUDBOMB0GA1UdDgQWBBRSLuBm
    rHPUGVJBF4SUgRe8QeqyJDAfBgNVHSMEGDAWgBRSLuBmrHPUGVJBF4SUgRe8Qeqy
    JDAMBgNVHRMEBTADAQH/MA0GCSqGSIb3DQEBDQUAA4ICAQDHDegbJTlVUPOtPORL
    +Q9GMKAsp47gOPuJlpuZ/x2++/R1h6r5/nj8iUh4Sp5S+d441SBiZifC0dyaLgnB
    vtTP2zcPE93CB3lq1h5U70gP2iw+kUcvd7jRirkHS4847O34WtOWBEtgw/zcJZHb
    Y24ssnlTxAdZwPHps3gWvgpb1A05JZfU2E99D7BiOH4rYakYB1yeKtR8Z6NCe/Vh
    GXqytCCrYVV+Nr4LA2fICqs8TnnmxKk2yr1mVbWmOBp8zGlNwNNz1c0kOmpYGlen
    or+aUaVC6K8tHzyDFU0oqI+8rEFP0nC2oYz6/kRh0I398APFOFqvCCla9TjoXTye
    kh0RucsWXkIjbxyBsDqbnwEDRVMiEsG8bgkk9uyKCgu+pj/SKyjar55ZKZlXOSdr
    fICZT409CRiB+Ng+g7lw8CPgY2fwwdavgQinZtI+q76VldlNuL+4nMHJzSnnR1Vl
    GXAPZ+Kk5sRWIlHX1qie3f2HKcKBnJnfMeC+n6UvXvyfs8bXNPKhu/NgEwu+hGgW
    W29ZVtqMt9iF1pLtMiS074ciUTNyFN4Ehy7UfYdWH7dpP3fDFMYkdIqBJxreF6TQ
    +RClYXpxSDN6Ri5g9m5z7isxjcwoLr82Ih/tyb7Ir8FUV0Hxj2MzbRD5mxN0TBka
    laPxVfOw5qoEpF6ZFc08u8AP8A==
    -----END CERTIFICATE-----
kind: ConfigMap
metadata:
  name: docker-cacerts

2. 准备DaemonSet资源文件

apiVersion: extensions/v1beta1
kind: DaemonSet
metadata:
  labels:
    deepexi-app: dockerca-mapper
  name: dockerca-mapper
spec:
  selector:
    matchLabels:
      deepexi-app: dockerca-mapper
  template:
    metadata:
      labels:
        deepexi-app: dockerca-mapper
    spec:
      containers:
      - command:
        - sleep
        - 365d
        image: busybox
        imagePullPolicy: IfNotPresent
        name: dockerca-mapper
        lifecycle:
          postStart:
            exec:
              command:
              - /bin/sh
              - -c
              - for i in `ls -1 /tmp-docker-certsd`;
                do
                  cert_dir=`echo $i | sed -e 's/\(_\)\([0-9]*\)$/:\2/g'`;
                  if [ ! -d /docker-certsd/$cert_dir ]; then
                    mkdir -p /docker-certsd/$cert_dir;
                  fi;
                  cp /tmp-docker-certsd/$i /docker-certsd/$cert_dir/ca.crt;
                done;
        volumeMounts:
        - mountPath: /tmp-docker-certsd
          name: tmp-docker-certsd
          readOnly: false
        - mountPath: /docker-certsd
          name: docker-certsd
          readOnly: false
      tolerations:
      - effect: NoExecute
        operator: Exists
      - effect: NoSchedule
        operator: Exists
      volumes:
      - hostPath:
          path: /etc/docker/certs.d
          type: DirectoryOrCreate
        name: docker-certsd
      - configMap:
          defaultMode: 440
          name: docker-cacerts
        name: tmp-docker-certsd

3. 应用配置到K8S集群

$ kubectl apply -f docker-ca-mapper.yaml -n ${obj_ns}

4. 验证

• 检查daemonset各节点Pod状态是否Running
• 检查/etc/docker/certs.d目录下相应仓库地址:端口目录及其下ca.crt文件是否存在
• 检查docker login仓库地址结果

$ kubectl get pod -n ${obj_ns} -o wide | grep dockerca-mapper
$ ls -l /etc/docker/certs.d/
$ docker login 10.50.32.5