Kubernetes

删除不一致状态下的 rc，deployment，service

在某些情况下，经常发现 kubectl 进程挂起现象，然后在 get 时候发现删了一半，而另外的删除不了

  1. [root@k8s-master ~]# kubectl get -f fluentd-elasticsearch/
  2. NAME DESIRED CURRENT READY AGE
  3. rc/elasticsearch-logging-v1 0 2 2 15h
  4. NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
  5. deploy/kibana-logging 0 1 1 1 15h
  6. Error from server (NotFound): services "elasticsearch-logging" not found
  7. Error from server (NotFound): daemonsets.extensions "fluentd-es-v1.22" not found
  8. Error from server (NotFound): services "kibana-logging" not found

删除这些 deployment，service 或者 rc 命令如下:

  1. kubectl delete deployment kibana-logging -n kube-system --cascade=false
  2. kubectl delete deployment kibana-logging -n kube-system  --ignore-not-found
  3. delete rc elasticsearch-logging-v1 -n kube-system --force now --grace-period=0
  4. 1|2删除不了后如何重置etcd

删除不了后如何重置 etcd

  1. rm -rf /var/lib/etcd/*

删除后重新 reboot master 结点。
reset etcd 后需要重新设置网络

  1. etcdctl mk /atomic.io/network/config '{ "Network": "192.168.0.0/16" }'

启动 apiserver 失败

每次启动都是报如下问题：

  1. start request repeated too quickly for kube-apiserver.service

但其实不是启动频率问题，需要查看/var/log/messages，这里的情况中是因为开启 ServiceAccount 后找不到 ca.crt 等文件，导致启动出错。

  1. May 21 07:56:41 k8s-master kube-apiserver: Flag --port has been deprecated, see --insecure-port instead.
  2. May 21 07:56:41 k8s-master kube-apiserver: F0521 07:56:41.692480 4299 universal_validation.go:104] Validate server run options failed: unable to load client CA file: open /var/run/kubernetes/ca.crt: no such file or directory
  3. May 21 07:56:41 k8s-master systemd: kube-apiserver.service: main process exited, code=exited, status=255/n/a
  4. May 21 07:56:41 k8s-master systemd: Failed to start Kubernetes API Server.
  5. May 21 07:56:41 k8s-master systemd: Unit kube-apiserver.service entered failed state.
  6. May 21 07:56:41 k8s-master systemd: kube-apiserver.service failed.
  7. May 21 07:56:41 k8s-master systemd: kube-apiserver.service holdoff time over, scheduling restart.
  8. May 21 07:56:41 k8s-master systemd: start request repeated too quickly for kube-apiserver.service
  9. May 21 07:56:41 k8s-master systemd: Failed to start Kubernetes API Server.

在部署 fluentd 等日志组件的时候，很多问题都是因为需要开启 ServiceAccount 选项需要配置安全导致，所以说到底还是需要配置好 ServiceAccount.

出现 Permission denied 情况

在配置 fluentd 时候出现cannot create /var/log/fluentd.log: Permission denied 错误，这是因为没有关掉 SElinux 安全导致。 :::tips 可以在 /etc/selinux/config 中将 SELINUX=enforcing 设置成 disabled,然后 reboot :::

基于 ServiceAccount 的配置

首先生成各种需要的 keys，k8s-master 需替换成 master 的主机名.

  1. openssl genrsa -out ca.key 2048
  2. openssl req -x509 -new -nodes -key ca.key -subj "/CN=k8s-master" -days 10000 -out ca.crt
  3. openssl genrsa -out server.key 2048
  4. echo subjectAltName=IP:10.254.0.1 > extfile.cnf
  5. #ip由下述命令决定
  6. #kubectl get services --all-namespaces |grep 'default'|grep 'kubernetes'|grep '443'|awk '{print $3}'
  7. openssl req -new -key server.key -subj "/CN=k8s-master" -out server.csr
  8. openssl x509 -req -in server.csr -CA ca.crt -CAkey ca.key -CAcreateserial -extfile extfile.cnf -out server.crt -days 10000

如果修改 /etc/kubernetes/apiserver 的配置文件参数的话，通过 systemctl start kube-apiserver 启动失败，出错信息为:

  1. Validate server run options failed: unable to load client CA file: open /root/keys/ca.crt: permission denied

但可以通过命令行启动 API Server

  1. /usr/bin/kube-apiserver --logtostderr=true --v=0 --etcd-servers=http://k8s-master:2379 --address=0.0.0.0 --port=8080 --kubelet-port=10250 --allow-privileged=true --service-cluster-ip-range=10.254.0.0/16 --admission-control=ServiceAccount --insecure-bind-address=0.0.0.0 --client-ca-file=/root/keys/ca.crt --tls-cert-file=/root/keys/server.crt --tls-private-key-file=/root/keys/server.key --basic-auth-file=/root/keys/basic_auth.csv --secure-port=443 &>> /var/log/kubernetes/kube-apiserver.log &

命令行启动 Controller-manager

  1. /usr/bin/kube-controller-manager --logtostderr=true --v=0 --master=http://k8s-master:8080 --root-ca-file=/root/keys/ca.crt --service-account-private-key-file=/root/keys/server.key & >>/var/log/kubernetes/kube-controller-manage.log

ETCD 启动不起来-问题<1>

etcd是kubernetes 集群的zookeeper进程，几乎所有的service都依赖于etcd的启动，比如flanneld,apiserver,docker…..在启动etcd是报错日志如下：

  1. May 24 13:39:09 k8s-master systemd: Stopped Flanneld overlay address etcd agent.
  2. May 24 13:39:28 k8s-master systemd: Starting Etcd Server...
  3. May 24 13:39:28 k8s-master etcd: recognized and used environment variable ETCD_ADVERTISE_CLIENT_URLS=http://etcd:2379,http://etcd:4001
  4. May 24 13:39:28 k8s-master etcd: recognized environment variable ETCD_NAME, but unused: shadowed by corresponding flag
  5. May 24 13:39:28 k8s-master etcd: recognized environment variable ETCD_DATA_DIR, but unused: shadowed by corresponding flag
  6. May 24 13:39:28 k8s-master etcd: recognized environment variable ETCD_LISTEN_CLIENT_URLS, but unused: shadowed by corresponding flag
  7. May 24 13:39:28 k8s-master etcd: etcd Version: 3.1.3
  8. May 24 13:39:28 k8s-master etcd: Git SHA: 21fdcc6
  9. May 24 13:39:28 k8s-master etcd: Go Version: go1.7.4
  10. May 24 13:39:28 k8s-master etcd: Go OS/Arch: linux/amd64
  11. May 24 13:39:28 k8s-master etcd: setting maximum number of CPUs to 1, total number of available CPUs is 1
  12. May 24 13:39:28 k8s-master etcd: the server is already initialized as member before, starting as etcd member...
  13. May 24 13:39:28 k8s-master etcd: listening for peers on http://localhost:2380
  14. May 24 13:39:28 k8s-master etcd: listening for client requests on 0.0.0.0:2379
  15. May 24 13:39:28 k8s-master etcd: listening for client requests on 0.0.0.0:4001
  16. May 24 13:39:28 k8s-master etcd: recovered store from snapshot at index 140014
  17. May 24 13:39:28 k8s-master etcd: name = master
  18. May 24 13:39:28 k8s-master etcd: data dir = /var/lib/etcd/default.etcd
  19. May 24 13:39:28 k8s-master etcd: member dir = /var/lib/etcd/default.etcd/member
  20. May 24 13:39:28 k8s-master etcd: heartbeat = 100ms
  21. May 24 13:39:28 k8s-master etcd: election = 1000ms
  22. May 24 13:39:28 k8s-master etcd: snapshot count = 10000
  23. May 24 13:39:28 k8s-master etcd: advertise client URLs = http://etcd:2379,http://etcd:4001
  24. May 24 13:39:28 k8s-master etcd: ignored file 0000000000000001-0000000000012700.wal.broken in wal
  25. May 24 13:39:29 k8s-master etcd: restarting member 8e9e05c52164694d in cluster cdf818194e3a8c32 at commit index 148905
  26. May 24 13:39:29 k8s-master etcd: 8e9e05c52164694d became follower at term 12
  27. May 24 13:39:29 k8s-master etcd: newRaft 8e9e05c52164694d [peers: [8e9e05c52164694d], term: 12, commit: 148905, applied: 140014, lastindex: 148905, lastterm: 12]
  28. May 24 13:39:29 k8s-master etcd: enabled capabilities for version 3.1
  29. May 24 13:39:29 k8s-master etcd: added member 8e9e05c52164694d [http://localhost:2380] to cluster cdf818194e3a8c32 from store
  30. May 24 13:39:29 k8s-master etcd: set the cluster version to 3.1 from store
  31. May 24 13:39:29 k8s-master etcd: starting server... [version: 3.1.3, cluster version: 3.1]
  32. May 24 13:39:29 k8s-master etcd: raft save state and entries error: open /var/lib/etcd/default.etcd/member/wal/0.tmp: is a directory
  33. May 24 13:39:29 k8s-master systemd: etcd.service: main process exited, code=exited, status=1/FAILURE
  34. May 24 13:39:29 k8s-master systemd: Failed to start Etcd Server.
  35. May 24 13:39:29 k8s-master systemd: Unit etcd.service entered failed state.
  36. May 24 13:39:29 k8s-master systemd: etcd.service failed.
  37. May 24 13:39:29 k8s-master systemd: etcd.service holdoff time over, scheduling restart.

核心语句：

  1. raft save state and entries error: open /var/lib/etcd/default.etcd/member/wal/0.tmp: is a directory

进入相关目录，删除 0.tmp，然后就可以启动了

ETCD启动不起来-超时问题<2>

问题背景：当前部署了 3 个 etcd 节点，突然有一天 3 台集群全部停电宕机了。重新启动之后发现 K8S 集群是可以正常使用的，但是检查了一遍组件之后，发现有一个节点的 etcd 启动不了。
经过一遍探查，发现时间不准确，通过以下命令 ntpdate ntp.aliyun.com 重新将时间调整正确，重新启动 etcd，发现还是起不来，报错如下：

  1. Mar 05 14:27:15 k8s-node2 etcd[3248]: etcd Version: 3.3.13
  2. Mar 05 14:27:15 k8s-node2 etcd[3248]: Git SHA: 98d3084
  3. Mar 05 14:27:15 k8s-node2 etcd[3248]: Go Version: go1.10.8
  4. Mar 05 14:27:15 k8s-node2 etcd[3248]: Go OS/Arch: linux/amd64
  5. Mar 05 14:27:15 k8s-node2 etcd[3248]: setting maximum number of CPUs to 4, total number of available CPUs is 4
  6. Mar 05 14:27:15 k8s-node2 etcd[3248]: the server is already initialized as member before, starting as etcd member
  7. ...
  8. Mar 05 14:27:15 k8s-node2 etcd[3248]: peerTLS: cert = /opt/etcd/ssl/server.pem, key = /opt/etcd/ssl/server-key.pe
  9. m, ca = , trusted-ca = /opt/etcd/ssl/ca.pem, client-cert-auth = false, crl-file =
  10. Mar 05 14:27:15 k8s-node2 etcd[3248]: listening for peers on https://192.168.25.226:2380
  11. Mar 05 14:27:15 k8s-node2 etcd[3248]: The scheme of client url http://127.0.0.1:2379 is HTTP while peer key/cert
  12. files are presented. Ignored key/cert files.
  13. Mar 05 14:27:15 k8s-node2 etcd[3248]: listening for client requests on 127.0.0.1:2379
  14. Mar 05 14:27:15 k8s-node2 etcd[3248]: listening for client requests on 192.168.25.226:2379
  15. Mar 05 14:27:15 k8s-node2 etcd[3248]: member 9c166b8b7cb6ecb8 has already been bootstrapped
  16. Mar 05 14:27:15 k8s-node2 systemd[1]: etcd.service: main process exited, code=exited, status=1/FAILURE
  17. Mar 05 14:27:15 k8s-node2 systemd[1]: Failed to start Etcd Server.
  18. Mar 05 14:27:15 k8s-node2 systemd[1]: Unit etcd.service entered failed state.
  19. Mar 05 14:27:15 k8s-node2 systemd[1]: etcd.service failed.
  20. Mar 05 14:27:15 k8s-node2 systemd[1]: etcd.service failed.
  21. Mar 05 14:27:15 k8s-node2 systemd[1]: etcd.service holdoff time over, scheduling restart.
  22. Mar 05 14:27:15 k8s-node2 systemd[1]: Starting Etcd Server...
  23. Mar 05 14:27:15 k8s-node2 etcd[3258]: recognized environment variable ETCD_NAME, but unused: shadowed by correspo
  24. nding flag
  25. Mar 05 14:27:15 k8s-node2 etcd[3258]: recognized environment variable ETCD_DATA_DIR, but unused: shadowed by corr
  26. esponding flag
  27. Mar 05 14:27:15 k8s-node2 etcd[3258]: recognized environment variable ETCD_LISTEN_PEER_URLS, but unused: shadowed
  28.  by corresponding flag
  29. Mar 05 14:27:15 k8s-node2 etcd[3258]: recognized environment variable ETCD_LISTEN_CLIENT_URLS, but unused: shadow
  30. ed by corresponding flag
  31. Mar 05 14:27:15 k8s-node2 etcd[3258]: recognized environment variable ETCD_INITIAL_ADVERTISE_PEER_URLS, but unuse
  32. d: shadowed by corresponding flag
  33. Mar 05 14:27:15 k8s-node2 etcd[3258]: recognized environment variable ETCD_ADVERTISE_CLIENT_URLS, but unused: sha
  34. dowed by corresponding flag
  35. Mar 05 14:27:15 k8s-node2 etcd[3258]: recognized environment variable ETCD_INITIAL_CLUSTER, but unused: shadowed
  36. by corresponding flag
  37. Mar 05 14:27:15 k8s-node2 etcd[3258]: recognized environment variable ETCD_INITIAL_CLUSTER_TOKEN, but unused: sha
  38. dowed by corresponding flag
  39. Mar 05 14:27:15 k8s-node2 etcd[3258]: recognized environment variable ETCD_INITIAL_CLUSTER_STATE, but unused: sha
  40. dowed by corresponding flag

解决方法

检查日志发现并没有特别明显的错误，根据经验来讲，etcd 节点坏掉一个其实对集群没有大的影响，这时集群已经可以正常使用了，但是这个坏掉的 etcd 节点并没有启动，解决方法如下：

  • 进入 etcd 的数据存储目录进行备份 备份原有数据：

    1. cd /var/lib/etcd/default.etcd/member/
    2. cp *  /data/bak/

  • 删除这个目录下的所有数据文件

    1. rm -rf /var/lib/etcd/default.etcd/member/*

  • 停止另外两台 etcd 节点，因为 etcd 节点启动时需要所有节点一起启动，启动成功后即可使用。

    1. #master 节点
    2. systemctl stop etcd
    3. systemctl restart etcd
    4. #node1 节点
    5. systemctl stop etcd
    6. systemctl restart etcd
    7. #node2 节点
    8. systemctl stop etcd
    9. systemctl restart etcd

    CentOS下配置主机互信

    在每台服务器需要建立主机互信的用户名执行以下命令生成公钥/密钥，默认回车即可

    1. ssh-keygen -t rsa

    可以看到生成个公钥的文件。
    互传公钥，第一次需要输入密码，之后就OK了。

    1. ssh-copy-id -i /root/.ssh/id_rsa.pub root@192.168.199.132 (-p 2222)

    -p 端口 默认端口不加-p，如果更改过端口，就得加上-p. 可以看到是在.ssh/下生成了个 authorized_keys的文件，记录了能登陆这台服务器的其他服务器的公钥。
    测试看是否能登陆：

    1. ssh 192.168.199.132 (-p 2222)

    CentOS 主机名的修改

    1. hostnamectl set-hostname k8s-master1

    Virtualbox 实现 CentOS 复制和粘贴功能

    如果不安装或者不输出，可以将 update 修改成 install 再运行。

    1. yum install update
    2. yum update kernel
    3. yum update kernel-devel
    4. yum install kernel-headers
    5. yum install gcc
    6. yum install gcc make

    运行完后

    1. sh VBoxLinuxAdditions.run

    删除Pod一直处于Terminating状态

    可以通过下面命令强制删除

    1. kubectl delete pod NAME --grace-period=0 --force

    删除namespace一直处于Terminating状态

    可以通过以下脚本强制删除

    1. [root@k8s-master1 k8s]# cat delete-ns.sh
    2. #!/bin/bash
    3. set -e
    4. useage(){
    5.   echo "useage:"
    6.   echo " delns.sh NAMESPACE"
    7. }
    8. if [ $# -lt 1 ];then
    9.   useage
    10.   exit
    11. fi
    12. NAMESPACE=$1
    13. JSONFILE=${NAMESPACE}.json
    14. kubectl get ns "${NAMESPACE}" -o json > "${JSONFILE}"
    15. vi "${JSONFILE}"
    16. curl -k -H "Content-Type: application/json" -X PUT --data-binary @"${JSONFLE}" \
    17.   http://127.0.0.1:8001/api/v1/namespaces/"${NAMESPACE}"/finalize

    容器包含有效的 CPU/内存 requests 且没有指定 limits 可能会出现什么问题？

    下面创建一个对应的容器，该容器只有 requests 设定，但是没有 limits 设定， ```yaml

  • name: busybox-cnt02 image: busybox command: [“/bin/sh”] args: [“-c”, “while true; do echo hello from cnt02; sleep 10;done”] resources:
    1. requests:
    2.   memory: "100Mi"
    3.   cpu: "100m"
    ```

    这个容器创建出来会有什么问题呢？

    其实对于正常的环境来说没有什么问题，但是对于资源型 pod 来说，如果有的容器没有设定 limit 限制，资源会被其他的 pod 抢占走，可能会造成容器应用失败的情况。可以通过 limitrange 策略来去匹配，让 pod 自动设定，前提是要提前配置好limitrange 规则。