K8s使用方法

1 查看k8s的版本信息

[root@k8s-master ~]# kubectl version

Client Version: version.Info{Major:"1", Minor:"5", GitVersion:"v1.5.2", GitCommit:"269f928217957e7126dc87e6adfa82242bfe5b1e", GitTreeState:"clean", BuildDate:"2017-07-03T15:31:10Z", GoVersion:"go1.7.4", Compiler:"gc", Platform:"linux/amd64"}

Server Version: version.Info{Major:"1", Minor:"5", GitVersion:"v1.5.2", GitCommit:"269f928217957e7126dc87e6adfa82242bfe5b1e", GitTreeState:"clean", BuildDate:"2017-07-03T15:31:10Z", GoVersion:"go1.7.4", Compiler:"gc", Platform:"linux/amd64"}

[root@k8s-master ~]# kubectl api-versions

apps/v1beta1

authentication.k8s.io/v1beta1

authorization.k8s.io/v1beta1

autoscaling/v1

batch/v1

certificates.k8s.io/v1alpha1

extensions/v1beta1

policy/v1beta1

rbac.authorization.k8s.io/v1alpha1

storage.k8s.io/v1beta1

2 查看各组件状态

[root@k8s-master yamls]# kubectl -s http://localhost:8080 get componentstatuses

NAME STATUS MESSAGE ERROR

etcd-0 Healthy {"health": "true"}

scheduler Healthy ok

controller-manager Healthy ok

3 查看k8s的组成节点（该节点指的是对应的服务器节点）

[root@k8s-master yamls]# kubectl get node

NAME STATUS AGE

192.168.248.142 Ready 18h

192.168.248.143 Ready 20s

4 确认Deployment

[root@k8s-master ~]# kubectl get deployment

NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE

foo 1 1 1 0 15h

my-nginx 2 2 2 2 14h

5 确认pod（该pod指的是对应的容器）

[root@k8s-master ~]# kubectl get pods

NAME READY STATUS RESTARTS AGE

foo-1189255365-3j6fr 0/1 CrashLoopBackOff 17 15h

my-nginx-379829228-pw1wj 1/1 Running 1 14h

my-nginx-379829228-wmlrt 1/1 Running 1 14h

6 删除pod

[root@k8s-master ~]# kubectl delete pods foo-1189255365-3j6fr

pod "foo-1189255365-3j6fr" deleted

确认结果看到foo-1189255365-3j6f为状态为CrashLoopBackOff这是确保replicas为1的动作，执行如下指令再次确认

[root@k8s-master ~]# kubectl get deployments

NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE

foo 1 1 1 0 15h

my-nginx 2 2 2 2 14h

删除deployment，直接删除pod触发replicas的确保机制，则可以删除deployment

[root@k8s-master ~]# kubectl delete deployment foo

deployment "foo" deleted

[root@k8s-master ~]# kubectl get pods

NAME READY STATUS RESTARTS AGE

my-nginx-379829228-pw1wj 1/1 Running 1 14h

my-nginx-379829228-wmlrt 1/1 Running 1 14h

7 通过yaml文件创建pod

[root@k8s-master yamls]# cat mysql.yaml

---

kind: ReplicationController

apiVersion: v1

metadata:

spec:

replicas: 1

selector:

template:

metadata:

labels:

spec:

containers:

- name: mysql

image: mysql:5.7.16

ports:

- containerPort: 3306

protocol: TCP

env:

- name: MYSQL_ROOT_PASSWORD

value: "hello123"

[root@k8s-master yamls]# cat sonar.yaml

---

kind: ReplicationController

apiVersion: v1

metadata:

spec:

replicas: 1

selector:

template:

metadata:

labels:

spec:

containers:

- name: sonarqube

image: sonarqube:5.6.5

ports:

- containerPort: 9000

protocol: TCP

8 创建mysql及sonarqube

创建mysql

[root@k8s-master yamls]# kubectl create -f mysql.yaml

replicationcontroller "mysql" created

[root@k8s-master yamls]# kubectl get pod

NAME READY STATUS RESTARTS AGE

my-nginx-379829228-pw1wj 1/1 Running 1 14h

my-nginx-379829228-wmlrt 1/1 Running 1 14h

mysql-vn2k3 1/1 Running 0 1m

[root@k8s-master yamls]# kubectl get rc

NAME DESIRED CURRENT READY AGE

mysql 1 1 1 2m

创建sonarqube

[root@k8s-master yamls]# kubectl create -f sonar.yaml

replicationcontroller "sonarqube" created

[root@k8s-master yamls]# kubectl get pod

NAME READY STATUS RESTARTS AGE

my-nginx-379829228-pw1wj 1/1 Running 1 15h

my-nginx-379829228-wmlrt 1/1 Running 1 15h

mysql-vn2k3 1/1 Running 0 18m

sonarqube-438sd 1/1 Running 0 2m

[root@k8s-master yamls]# kubectl delete -f mysql.yaml

[root@k8s-master yamls]# kubectl delete -f sonar.yaml

9 描述某一个pod的详细信息

[root@k8s-master yamls]# kubectl describe pod mysql-vn2k3

Name: mysql-vn2k3

Namespace: default

Node: 192.168.248.142/192.168.248.142

Start Time: Thu, 11 Oct 2018 18:28:04 -0700

Labels: name=mysql

Status: Running

IP: 172.17.0.3

Controllers: ReplicationController/mysql

Containers:

mysql:

Container ID: docker://4cdbb18e4a4d863a6f777b7738125f42a80eb6c071bc62573d045b984df5744b

Image: mysql:5.7.16

Image ID: docker-pullable://docker.io/mysql@sha256:89cc6ff6a7ac9916c3384e864fb04b8ee9415b572f872a2a4cf5b909dbbca81b

Port: 3306/TCP

State: Running

Started: Thu, 11 Oct 2018 18:29:44 -0700

Ready: True

Restart Count: 0

Volume Mounts: <none>

Environment Variables:

MYSQL_ROOT_PASSWORD: hello123

Conditions:

Type Status

Initialized True

Ready True

PodScheduled True

No volumes.

QoS Class: BestEffort

Tolerations: <none>

Events:

FirstSeen LastSeen Count From SubObjectPath Type Reason Message

--------- -------- ----- ---- ------------- -------- ------ -------

26m 26m 1 {default-scheduler } Normal Scheduled Successfully assigned mysql-vn2k3 to 192.168.248.142

26m 26m 1 {kubelet 192.168.248.142} spec.containers{mysql} Normal Pulling pulling image "mysql:5.7.16"

26m 25m 2 {kubelet 192.168.248.142} Warning MissingClusterDNS kubelet does not have ClusterDNS IP configured and cannot create Pod using "ClusterFirst" policy. Falling back to DNSDefault policy.

25m 25m 1 {kubelet 192.168.248.142} spec.containers{mysql} Normal Pulled Successfully pulled image "mysql:5.7.16"

24m 24m 1 {kubelet 192.168.248.142} spec.containers{mysql} Normal Created Created container with docker id 4cdbb18e4a4d; Security:[seccomp=unconfined]

24m 24m 1 {kubelet 192.168.248.142} spec.containers{mysql} Normal Started Started container with docker id 4cdbb18e4a4d

10 scale

scale用于程序在负载加重或缩小时副本进行扩容或缩小，如前面创建的nginx有两个副本，可以轻松的使用scale命令对副本数进行扩展或缩小。
扩展副本数到4：

[root@k8s-master yamls]# kubectl scale rc mysql --replicas=4

replicationcontroller "mysql" scaled

[root@k8s-master yamls]# kubectl get rc

[root@k8s-master ~]# kubectl get rc

NAME DESIRED CURRENT READY AGE

mysql 2 2 2 1h

sonarqube 1 1 1 1h

重新缩减副本数到2：

[root@k8s-master yamls]# kubectl scale rc mysql --replicas=2

replicationcontroller "mysql" scaled

[root@k8s-master yamls]# kubectl get pod

NAME READY STATUS RESTARTS AGE

my-nginx-379829228-pw1wj 1/1 Running 1 15h

my-nginx-379829228-wmlrt 1/1 Running 1 15h

mysql-8wz8j 1/1 Running 0 1m

mysql-vn2k3 1/1 Running 0 50m

sonarqube-438sd 1/1 Running 0 33m

11获取指定json或ymal格式的KEY数据,custom-columns=XXXXX（自定义列名）:.status.hostIP（以“点开始”，然后写路径就可以）:

[root@k8s-master yamls]# kubectl get pod mysql-vn2k3 -o custom-columns=HOST-IP:.status.hostIP,POD-IP:.status.podIP

HOST-IP POD-IP

192.168.248.142 172.17.0.3

12 查看某个pod重启次数

[root@k8s-master ~]# kubectl get pod my-nginx-379829228-pw1wj --template="{{range .status.containerStatuses}}{{.name}}:{{.restartCount}}{{end}}"

my-nginx:1

13 查看pod的生命周期

[root@k8s-master ~]# kubectl get pod sonarqube-438sd --template="{{.status.phase}}"

Running

14 容器内日志输出

logs命令用于显示pod运行中，容器内程序输出到标准输出的内容。跟docker的logs命令类似。如果要获得tail -f 的方式，也可以使用-f选项。

[root@k8s-master ~]# kubectl logs mysql-8wz8j

Initializing database

2018-10-12T02:16:34.904907Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).

2018-10-12T02:16:40.315744Z 0 [Warning] InnoDB: New log files created, LSN=45790

2018-10-12T02:16:44.441289Z 0 [Warning] InnoDB: Creating foreign key constraint system tables.

2018-10-12T02:16:48.178465Z 0 [Warning] No existing UUID has been found, so we assume that this is the first time that this server has been started. Generating a new UUID: df7fe121-cdc4-11e8-a664-0242ac110006.

2018-10-12T02:16:48.221676Z 0 [Warning] Gtid table is not ready to be used. Table 'mysql.gtid_executed' cannot be opened.

2018-10-12T02:16:48.239652Z 1 [Warning] root@localhost is created with an empty password ! Please consider switching off the --initialize-insecure option.

2018-10-12T02:16:53.319037Z 1 [Warning] 'user' entry 'root@localhost' ignored in --skip-name-resolve mode.

2018-10-12T02:16:53.324377Z 1 [Warning] 'user' entry 'mysql.sys@localhost' ignored in --skip-name-resolve mode.

2018-10-12T02:16:53.324458Z 1 [Warning] 'db' entry 'sys mysql.sys@localhost' ignored in --skip-name-resolve mode.

2018-10-12T02:16:53.327143Z 1 [Warning] 'proxies_priv' entry '@ root@localhost' ignored in --skip-name-resolve mode.

2018-10-12T02:16:53.327271Z 1 [Warning] 'tables_priv' entry 'sys_config mysql.sys@localhost' ignored in --skip-name-resolve mode.

Database initialized

MySQL init process in progress...

2018-10-12T02:17:22.381789Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).

2018-10-12T02:17:25.089076Z 0 [Note] mysqld (mysqld 5.7.16) starting as process 53 ...

2018-10-12T02:17:25.419875Z 0 [Note] InnoDB: PUNCH HOLE support available

2018-10-12T02:17:25.422563Z 0 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins

2018-10-12T02:17:25.424559Z 0 [Note] InnoDB: Uses event mutexes

2018-10-12T02:17:25.424598Z 0 [Note] InnoDB: GCC builtin __atomic_thread_fence() is used for memory barrier

2018-10-12T02:17:25.425938Z 0 [Note] InnoDB: Compressed tables use zlib 1.2.3

2018-10-12T02:17:25.426742Z 0 [Note] InnoDB: Using Linux native AIO

2018-10-12T02:17:25.434586Z 0 [Note] InnoDB: Number of pools: 1

2018-10-12T02:17:25.446547Z 0 [Note] InnoDB: Using CPU crc32 instructions

15 autoscale

scale虽然能够很方便的对副本数进行扩展或缩小，但是仍然需要人工介入，不能实时自动的根据系统负载对副本数进行扩、缩。autoscale命令提供了自动根据pod负载对其副本进行扩缩的功能。

autoscale命令会给一个rc指定一个副本数的范围，在实际运行中根据pod中运行的程序的负载自动在指定的范围内对pod进行扩容或缩容。如前面创建的nginx，可以用如下命令指定副本范围在1~4

[root@k8s-master ~]# kubectl autoscale rc sonarqube --min=1 --max=4

replicationcontroller "sonarqube" autoscaled

16 查看容器运行在哪个node节点

[root@k8s-master ~]# kubectl get pod -o wide

NAME READY STATUS RESTARTS AGE IP NODE

my-nginx-379829228-pw1wj 1/1 Running 1 17h 172.17.0.2 192.168.248.142

my-nginx-379829228-wmlrt 1/1 Running 1 17h 172.17.0.4 192.168.248.142

mysql-8wz8j 1/1 Running 0 1h 172.17.0.6 192.168.248.142

mysql-vn2k3 1/1 Running 0 2h 172.17.0.3 192.168.248.142

sonarqube-438sd 1/1 Running 0 1h 172.17.0.5 192.168.248.142

testnginx-94870464-9nkxn 1/1 Running 0 1m 172.17.0.5 192.168.248.143

testnginx-94870464-k3hdg 1/1 Running 0 1m 172.17.0.4 192.168.248.143

testnginx-94870464-r208x 1/1 Running 0 1m 172.17.0.7 192.168.248.142

testnginx-94870464-s9c9x 1/1 Running 0 1m 172.17.0.8 192.168.248.142

testnginx-94870464-sz6pb 1/1 Running 0 1m 172.17.0.3 192.168.248.143

younginx-2413665018-q2nvq 1/1 Running 0 53m 172.17.0.2 192.168.248.143

16 cordon, drain, uncordon

这三个命令是正式release的1.2新加入的命令，三个命令一起介绍，是因为三个命令配合使用可以实现节点的维护。在1.2之前，因为没有相应的命令支持，如果要维护一个节点，只能stop该节点上的kubelet将该节点退出集群，是集群不在将新的pod调度到该节点上。如果该节点上本生就没有pod在运行，则不会对业务有任何影响。如果该节点上有pod正在运行，kubelet停止后，master会发现该节点不可达，而将该节点标记为notReady状态，不会将新的节点调度到该节点上。同时，会在其他节点上创建新的pod替换该节点上的pod。这种方式虽然能够保证集群的健壮性，但是任然有些暴力，如果业务只有一个副本，而且该副本正好运行在被维护节点上的话，可能仍然会造成业务的短暂中断。

1.2中新加入的这3个命令可以保证维护节点时，平滑的将被维护节点上的业务迁移到其他节点上，保证业务不受影响。如下图所示是一个整个的节点维护的流程（为了方便demo增加了一些查看节点信息的操作）：1）首先查看当前集群所有节点状态，可以看到共四个节点都处于ready状态；2）查看当前nginx两个副本分别运行在k8s-node和k8s-node1两个节点上；3）使用cordon命令将k8s-node1标记为不可调度；4）再使用kubectl get nodes查看节点状态，发现k8s-node1虽然还处于Ready状态，但是同时还被禁能了调度，这意味着新的pod将不会被调度到k8s-node1上。4）再查看nginx状态，没有任何变化，两个副本仍运行在k8s-node和k8s-node1上；5）执行drain命令，将运行在k8s-node1上运行的pod平滑的赶到其他节点上；6）再查看nginx的状态发现，k8s-node1上的副本已经被迁移到k8s-node上；这时候就可以对k8s-node1进行一些节点维护的操作，如升级内核，升级Docker等；7）节点维护完后，使用uncordon命令解锁k8s-node1，使其重新变得可调度；8）检查节点状态，发现k8s-node1重新变回Ready状态

[root@k8s-master ~]# kubectl get node

NAME STATUS AGE

192.168.248.142 Ready 19h

192.168.248.143 Ready 1h

[root@k8s-master ~]# kubectl cordon 192.168.248.143

node "192.168.248.143" cordoned

[root@k8s-master ~]# kubectl get node

NAME STATUS AGE

192.168.248.142 Ready 19h

192.168.248.143 Ready,SchedulingDisabled 1h

[root@k8s-master ~]# kubectl get pod -o wide

NAME READY STATUS RESTARTS AGE IP NODE

my-nginx-379829228-pw1wj 1/1 Running 1 17h 172.17.0.2 192.168.248.142

my-nginx-379829228-wmlrt 1/1 Running 1 17h 172.17.0.4 192.168.248.142

mysql-8wz8j 1/1 Running 0 1h 172.17.0.6 192.168.248.142

mysql-vn2k3 1/1 Running 0 2h 172.17.0.3 192.168.248.142

sonarqube-438sd 1/1 Running 0 2h 172.17.0.5 192.168.248.142

testnginx-94870464-9nkxn 1/1 Running 0 12m 172.17.0.5 192.168.248.143

testnginx-94870464-k3hdg 1/1 Running 0 12m 172.17.0.4 192.168.248.143

testnginx-94870464-r208x 1/1 Running 0 12m 172.17.0.7 192.168.248.142

testnginx-94870464-s9c9x 1/1 Running 0 12m 172.17.0.8 192.168.248.142

testnginx-94870464-sz6pb 1/1 Running 0 12m 172.17.0.3 192.168.248.143

younginx-2413665018-q2nvq 1/1 Running 0 1h 172.17.0.2 192.168.248.143

[root@k8s-master ~]# kubectl drain 192.168.248.143

node "192.168.248.143" already cordoned

pod "testnginx-94870464-sz6pb" evicted

pod "testnginx-94870464-k3hdg" evicted

pod "younginx-2413665018-q2nvq" evicted

pod "testnginx-94870464-9nkxn" evicted

node "192.168.248.143" drained

[root@k8s-master ~]# kubectl uncordon 192.168.248.143

node "192.168.248.143" uncordoned

[root@k8s-master ~]# kubectl get pod -o wide

NAME READY STATUS RESTARTS AGE IP NODE

my-nginx-379829228-pw1wj 1/1 Running 1 18h 172.17.0.2 192.168.248.142

my-nginx-379829228-wmlrt 1/1 Running 1 18h 172.17.0.4 192.168.248.142

mysql-8wz8j 1/1 Running 0 2h 172.17.0.6 192.168.248.142

mysql-vn2k3 1/1 Running 0 3h 172.17.0.3 192.168.248.142

sonarqube-438sd 1/1 Running 0 3h 172.17.0.5 192.168.248.142

testnginx-94870464-57pkj 1/1 Running 0 55m 172.17.0.11 192.168.248.142

testnginx-94870464-dgqdg 1/1 Running 0 55m 172.17.0.9 192.168.248.142

testnginx-94870464-r208x 1/1 Running 0 1h 172.17.0.7 192.168.248.142

testnginx-94870464-s9c9x 1/1 Running 0 1h 172.17.0.8 192.168.248.142

testnginx-94870464-zhq8g 1/1 Running 0 55m 172.17.0.10 192.168.248.142

younginx-2413665018-djpr4 1/1 Running 0 55m 172.17.0.12 192.168.248.142

17 rolling-update

rolling-update是一个非常重要的命令，对于已经部署并且正在运行的业务，rolling-update提供了不中断业务的更新方式。rolling-update每次起一个新的pod，等新pod完全起来后删除一个旧的pod，然后再起一个新的pod替换旧的pod，直到替换掉所有的pod。

rolling-update需要确保新的版本有不同的name，Version和label，否则会报错。

18 edit

edit提供了另一种更新resource源的操作，通过edit能够灵活的在一个common的resource基础上，发展出更过的significant resource。

[root@k8s-master yamls]# kubectl get pod mysql-vn2k3 -o yaml >> /tmp/mysql-tmp.yaml

[root@k8s-master yamls]# cd /tmp

[root@k8s-master tmp]# ls

firefox_wzf mysql-tmp.yaml systemd-private-d1eff1b44a034169825ab8953453f7b1-rtkit-daemon.service-mZYosX vmware-config0

hsperfdata_root ssh-oGW5Z3EQV1MZ Temp-06a78ebe-5e0b-4213-9d60-db80b8bb4c47 vmware-root

ks-script-5YmpDP systemd-private-d1eff1b44a034169825ab8953453f7b1-chronyd.service-n8j5ru tmp.nLlvBLCtsm yum.log

ks-script-IH2Z_2 systemd-private-d1eff1b44a034169825ab8953453f7b1-colord.service-HAlGh3 tmp.tzkmKHEunU yum_save_tx.2018-10-11.00-34.fI_o2U.yumtx

lua_a0C7G7 systemd-private-d1eff1b44a034169825ab8953453f7b1-cups.service-bsrX2b tracker-extract-files.1000

[root@k8s-master tmp]# vim mysql-tmp.yaml

/做一些配置文件的修改/

kubectl replace –f mysql-tmp.yaml

19如果一个容器已经在运行，这时需要对一些容器属性进行修改，又不想删除容器，或不方便通过replace的方式进行更新。kubernetes还提供了一种在容器运行时，直接对容器进行修改的方式，就是patch命令。

如前面创建pod的label是app=nginx-2，如果在运行过程中，需要把其label改为app=nginx-3。

[root@k8s-master ~]# kubectl patch pod my-nginx-379829228-pw1wj -p '{"metadata":{"labels":{"app":"nginx-3"}}}'

20 replace更新替换资源

replace命令用于对已有资源进行更新、替换。如前面create中创建的mysql，当我们需要更新resource的一些属性的时候，如果修改副本数量，增加、修改label，更改image版本，修改端口等。都可以直接修改原yaml文件，然后执行replace命令。

注：名字不能被更更新。另外，如果是更新label，原有标签的pod将会与更新label后的rc断开联系，有新label的rc将会创建指定副本数的新的pod，但是默认并不会删除原来的pod。所以此时如果使用get po将会发现pod数翻倍，进一步check会发现原来的pod已经不会被新rc控制

kubectl replace -f mysql.yaml

21测试稳定性

在node上通过docker stop $(docker ps -a -q)停止容器，发现k8s会自动重新生成新容器

[root@k8s-node ~]# docker stop $(docker ps -a -q)

d6245b7cd653

82c2032630cf

6c63dd03bd40

f2ed49c519d4

b3e1d844a4bd

bcde1cbffb77

4dad2b30e835

2b2c3c3bd62e

72535e112570

e04d5be2b2ca

8f49e0d5dcf4

9ec557300ec5

3469ee4b3fa6

cb8c74f84229

8d5a48ea55a7

f8f68f273f3a

911281e9ff32

6efd0d3ff39c

e893bceabce6

4cdbb18e4a4d

bf6c67772f1d

350faeb2a846

562c22f0f72c

3eb1470101f0

aaae22de2e1f

[root@k8s-node ~]# docker ps -a

CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES

d7de526077a9 nginx "nginx -g 'daemon ..." 1 second ago Up Less than a second k8s_testnginx.affadd93_testnginx-94870464-dgqdg_default_3f639a8e-cdd2-11e8-94c7-000c29ee98c6_429fea38

9ef0ed5e1452 registry.access.redhat.com/rhel7/pod-infrastructure:latest "/usr/bin/pod" 3 seconds ago Up Less than a second k8s_POD.1d520ba5_mysql-vn2k3_default_110cf8c4-cdbe-11e8-94c7-000c29ee98c6_c7954e7c

86d6620c4b61 mysql:5.7.16 "docker-entrypoint..." 3 seconds ago Up 2 seconds k8s_mysql.f4f82081_mysql-8wz8j_default_cfab4bb8-cdc4-11e8-94c7-000c29ee98c6_a9707fc2

20c1db52c18a sonarqube:5.6.5 "./bin/run.sh" 4 seconds ago Up 2 seconds k8s_sonarqube.5a6904a7_sonarqube-438sd_default_4eeb9745-cdc0-11e8-94c7-000c29ee98c6_3d66d17e

ca136f13a08d registry.access.redhat.com/rhel7/pod-infrastructure:latest "/usr/bin/pod" 6 seconds ago Up 3 seconds k8s_POD.1d520ba5_mysql-8wz8j_default_cfab4bb8-cdc4-11e8-94c7-000c29ee98c6_bd4258af

49c191c3debe nginx "nginx -g 'daemon ..." 7 seconds ago Up 3 seconds k8s_my-nginx.a65fe6c_my-nginx-379829228-pw1wj_default_75a3218b-cd41-11e8-993b-000c29ee98c6_d78f4ca0

2ca27f74d8cc registry.access.redhat.com/rhel7/pod-infrastructure:latest "/usr/bin/pod" 7 seconds ago Up 4 seconds k8s_POD.17af0ba2_sonarqube-438sd_default_4eeb9745-cdc0-11e8-94c7-000c29ee98c6_4bc68f43

720ca258413e registry.access.redhat.com/rhel7/pod-infrastructure:latest "/usr/bin/pod" 8 seconds ago Up 4 seconds k8s_POD.ae8ee9ac_testnginx-94870464-r208x_default_4d8fdaed-cdd0-11e8-94c7-000c29ee98c6_c1d37620

95dfffa18d88 registry.access.redhat.com/rhel7/pod-infrastructure:latest "/usr/bin/pod" 10 seconds ago Up 8 seconds k8s_POD.ae8ee9ac_testnginx-94870464-57pkj_default_3f6368c2-cdd2-11e8-94c7-000c29ee98c6_2b0a6b54

5557753c36c8 registry.access.redhat.com/rhel7/pod-infrastructure:latest "/usr/bin/pod" 12 seconds ago Up 10 seconds k8s_POD.a8590b41_my-nginx-379829228-wmlrt_default_75a284fc-cd41-11e8-993b-000c29ee98c6_5174be7e

9b99654e2f98 registry.access.redhat.com/rhel7/pod-infrastructure:latest "/usr/bin/pod" 12 seconds ago Up 10 seconds k8s_POD.ae8ee9ac_testnginx-94870464-zhq8g_default_3f51dbae-cdd2-11e8-94c7-000c29ee98c6_b422e753

c76dcef68f3b registry.access.redhat.com/rhel7/pod-infrastructure:latest "/usr/bin/pod" 14 seconds ago Up 11 seconds k8s_POD.ae8ee9ac_testnginx-94870464-s9c9x_default_4d8f42b0-cdd0-11e8-94c7-000c29ee98c6_a07a56a6

bdee5d0dcf94 registry.access.redhat.com/rhel7/pod-infrastructure:latest "/usr/bin/pod" 15 seconds ago Up 13 seconds k8s_POD.ae8ee9ac_younginx-2413665018-djpr4_default_3f52038e-cdd2-11e8-94c7-000c29ee98c6_581d115a

3e45d88946e4 registry.access.redhat.com/rhel7/pod-infrastructure:latest "/usr/bin/pod" 19 seconds ago Up 15 seconds k8s_POD.ae8ee9ac_testnginx-94870464-dgqdg_default_3f639a8e-cdd2-11e8-94c7-000c29ee98c6_06050950

42d8b7f25787 registry.access.redhat.com/rhel7/pod-infrastructure:latest "/usr/bin/pod" 19 seconds ago Up 15 seconds k8s_POD.a8590b41_my-nginx-379829228-pw1wj_default_75a3218b-cd41-11e8-993b-000c29ee98c6_3b93844c

8f017385d1f8 registry.access.redhat.com/rhel7/pod-infrastructure:latest "/usr/bin/pod" 22 seconds ago Created k8s_POD.ae8ee9ac_testnginx-94870464-r208x_default_4d8fdaed-cdd0-11e8-94c7-000c29ee98c6_db46c731

730a53238394 registry.access.redhat.com/rhel7/pod-infrastructure:latest "/usr/bin/pod" 22 seconds ago Created k8s_POD.1d520ba5_mysql-vn2k3_default_110cf8c4-cdbe-11e8-94c7-000c29ee98c6_23252339

06234eb7bc47 registry.access.redhat.com/rhel7/pod-infrastructure:latest "/usr/bin/pod" 23 seconds ago Created k8s_POD.1d520ba5_mysql-8wz8j_default_cfab4bb8-cdc4-11e8-94c7-000c29ee98c6_9f5893a2

59258eb463ad registry.access.redhat.com/rhel7/pod-infrastructure:latest "/usr/bin/pod" 44 seconds ago Created k8s_POD.1d520ba5_mysql-vn2k3_default_110cf8c4-cdbe-11e8-94c7-000c29ee98c6_9fdc5868

8203403a4b26 registry.access.redhat.com/rhel7/pod-infrastructure:latest "/usr/bin/pod" 48 seconds ago Created k8s_POD.1d520ba5_mysql-8wz8j_default_cfab4bb8-cdc4-11e8-94c7-000c29ee98c6_89d3d41b

7fec434356b3 registry.access.redhat.com/rhel7/pod-infrastructure:latest "/usr/bin/pod" 51 seconds ago Created k8s_POD.a8590b41_my-nginx-379829228-wmlrt_default_75a284fc-cd41-11e8-993b-000c29ee98c6_72d9e2e8

d562725bb32a registry.access.redhat.com/rhel7/pod-infrastructure:latest "/usr/bin/pod" 55 seconds ago Created k8s_POD.a8590b41_my-nginx-379829228-pw1wj_default_75a3218b-cd41-11e8-993b-000c29ee98c6_957a8f06

aed15bcffdad registry.access.redhat.com/rhel7/pod-infrastructure:latest "/usr/bin/pod" 58 seconds ago Created k8s_POD.ae8ee9ac_testnginx-94870464-dgqdg_default_3f639a8e-cdd2-11e8-94c7-000c29ee98c6_f720e

备注：RC(Replication Controller)

Replication Controller确保任何时候Kubernetes集群中有指定数量的pod副本(replicas)在运行，如果少于指定数量的pod副本(replicas)，Replication Controller会启动新的Container，反之会杀死多余的以保证数量不变。Replication Controller使用预先定义的pod模板创建pods，一旦创建成功，pod 模板和创建的pods没有任何关联，可以修改pod 模板而不会对已创建pods有任何影响，也可以直接更新通过Replication Controller创建的pods。对于利用pod 模板创建的pods，Replication Controller根据label selector来关联，通过修改pods的label可以删除对应的pods。

22 进入创建的pod内

[root@k8s-master ~]# kubectl get pod

NAME READY STATUS RESTARTS AGE

my-nginx-379829228-pw1wj 1/1 Running 2 19h

my-nginx-379829228-wmlrt 1/1 Running 2 19h

mysql-8wz8j 1/1 Running 1 4h

mysql-vn2k3 1/1 Running 1 4h

sonarqube-438sd 1/1 Running 1 4h

testnginx-94870464-57pkj 1/1 Running 1 2h

testnginx-94870464-dgqdg 1/1 Running 1 2h

testnginx-94870464-r208x 1/1 Running 1 2h

testnginx-94870464-s9c9x 1/1 Running 1 2h

testnginx-94870464-zhq8g 1/1 Running 1 2h

younginx-2413665018-djpr4 1/1 Running 1 2h

[root@k8s-master ~]# kubectl exec my-nginx-379829228-pw1wj date

Fri Oct 12 06:27:59 UTC 2018

[root@k8s-master ~]# kubectl exec my-nginx-379829228-pw1wj -it bash

root@my-nginx-379829228-pw1wj:/# ifconfig

23 attach

attach命令类似于docker的attach命令，可以直接查看容器中以daemon形式运行的进程的输出，效果类似于logs -f，退出查看使用ctrl-c。

[root@k8s-master ~]# kubectl get pod

NAME READY STATUS RESTARTS AGE

my-nginx-379829228-pw1wj 1/1 Running 2 21h

my-nginx-379829228-wmlrt 1/1 Running 2 21h

mysql-8wz8j 1/1 Running 1 5h

mysql-vn2k3 1/1 Running 1 6h

sonarqube-438sd 1/1 Running 1 6h

testnginx-94870464-57pkj 1/1 Running 1 4h

testnginx-94870464-dgqdg 1/1 Running 1 4h

testnginx-94870464-r208x 1/1 Running 1 4h

testnginx-94870464-s9c9x 1/1 Running 1 4h

testnginx-94870464-zhq8g 1/1 Running 1 4h

younginx-2413665018-djpr4 1/1 Running 1 4h

[root@k8s-master ~]# kubectl attach mysql-vn2k3

If you don't see a command prompt, try pressing enter.

Initializing database

2018-10-12T06:08:05.686626Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).

2018-10-12T06:08:08.351170Z 0 [Warning] InnoDB: New log files created, LSN=45790

2018-10-12T06:08:08.865590Z 0 [Warning] InnoDB: Creating foreign key constraint system tables.

2018-10-12T06:08:08.976485Z 0 [Warning] No existing UUID has been found, so we assume that this is the first time that this server has been started. Generating a new UUID: 311992bb-cde5-11e8-beb9-0242ac11000c.

2018-10-12T06:08:08.979892Z 0 [Warning] Gtid table is not ready to be used. Table 'mysql.gtid_executed' cannot be opened.

2018-10-12T06:08:08.990000Z 1 [Warning] root@localhost is created with an empty password ! Please consider switching off the --initialize-insecure option.

2018-10-12T06:08:13.469651Z 1 [Warning] 'user' entry 'root@localhost' ignored in --skip-name-resolve mode.

2018-10-12T06:08:13.473797Z 1 [Warning] 'user' entry 'mysql.sys@localhost' ignored in --skip-name-resolve mode.

2018-10-12T06:08:13.473872Z 1 [Warning] 'db' entry 'sys mysql.sys@localhost' ignored in --skip-name-resolve mode.

2018-10-12T06:08:13.473904Z 1 [Warning] 'proxies_priv' entry '@ root@localhost' ignored in --skip-name-resolve mode.

2018-10-12T06:08:13.473994Z 1 [Warning] 'tables_priv' entry 'sys_config mysql.sys@localhost' ignored in --skip-name-resolve mode.

Database initialized

MySQL init process in progress...

2018-10-12T06:08:18.765789Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).

2018-10-12T06:08:18.853393Z 0 [Note] mysqld (mysqld 5.7.16) starting as process 53 ...

MySQL init process in progress...

2018-10-12T06:08:42.181567Z 0 [Note] InnoDB: PUNCH HOLE support available

2018-10-12T06:08:42.376104Z 0 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins

2018-10-12T06:08:42.376825Z 0 [Note] InnoDB: Uses event mutexes

2018-10-12T06:08:42.376866Z 0 [Note] InnoDB: GCC builtin __atomic_thread_fence() is used for memory barrier

2018-10-12T06:08:42.376879Z 0 [Note] InnoDB: Compressed tables use zlib 1.2.3

2018-10-12T06:08:42.376890Z 0 [Note] InnoDB: Using Linux native AIO

2018-10-12T06:08:42.384160Z 0 [Note] InnoDB: Number of pools: 1