Docker Swarm 2020(1)Simply Install and Use Swarm

Docker Swarm 2020(1)Simply Install and Use Swarm

Check my Docker
> docker --version
Docker version 19.03.8, build afacb8b

Swarm Manager - rancher-home
Swarm Worker - rancher-worker1
Swarm Worker - rancher-worker2

Some useful ports:
2377 - cluster management
7946 - node to node
4789 - overlay network

On rancher-home
> docker swarm init --advertise-addr 192.168.56.110
Swarm initialized: current node (st1b4xuylrj6mm5oggsk6hp04) is now a manager.
To add a worker to this swarm, run the following command:
    docker swarm join --token SWMTKN-1-3ak17tlxe1ljqv8pk7gn1kwrjbz9hzgkn48wh8vu27o39ypjf6-b4mxpq45n2y0i6dpel3hwjlyw 192.168.56.110:2377
To add a manager to this swarm, run 'docker swarm join-token manager' and follow the instructions.

If I forget about the token information just in case
> docker swarm join-token worker
To add a worker to this swarm, run the following command:
    docker swarm join --token SWMTKN-1-3ak17tlxe1ljqv8pk7gn1kwrjbz9hzgkn48wh8vu27o39ypjf6-b4mxpq45n2y0i6dpel3hwjlyw 192.168.56.110:2377

> docker info
Swarm: active
  NodeID: st1b4xuylrj6mm5oggsk6hp04
  Is Manager: true
  ClusterID: linol1nuatvwjbvquh1fg7x8h
  Managers: 1
  Nodes: 1
  Default Address Pool: 10.0.0.0/8 
  SubnetSize: 24
  Data Path Port: 4789

> docker node ls
ID                            HOSTNAME            STATUS              AVAILABILITY        MANAGER STATUS      ENGINE VERSION
st1b4xuylrj6mm5oggsk6hp04 *   rancher-home        Ready               Active              Leader              19.03.8

Add the worker node to the swarm cluster
On rancher-worker1
> docker --version
Docker version 19.03.8, build afacb8b

Join the cluster
> docker swarm join --token SWMTKN-1-3ak17tlxe1ljqv8pk7gn1kwrjbz9hzgkn48wh8vu27o39ypjf6-b4mxpq45n2y0i6dpel3hwjlyw 192.168.56.110:2377

On rancher-worker2
> docker --version
Docker version 19.03.8, build afacb8b

> docker swarm join --token SWMTKN-1-3ak17tlxe1ljqv8pk7gn1kwrjbz9hzgkn48wh8vu27o39ypjf6-b4mxpq45n2y0i6dpel3hwjlyw 192.168.56.110:2377

On the manager machine, we can see all the nodes
> docker node ls
ID                            HOSTNAME            STATUS              AVAILABILITY        MANAGER STATUS      ENGINE VERSION
st1b4xuylrj6mm5oggsk6hp04 *   rancher-home        Ready               Active              Leader              19.03.8
d85e6hmp2saf2xfyiq8nopvkp     rancher-worker1     Ready               Active                                  19.03.8
ccr3520glvgpyg7dn1zbkr8zg     rancher-worker2     Ready               Active                                  19.03.8

Remove the node from cluster
> docker swarm leave
Node left the swarm.

> docker node ls
ID                            HOSTNAME            STATUS              AVAILABILITY        MANAGER STATUS      ENGINE VERSION
st1b4xuylrj6mm5oggsk6hp04 *   rancher-home        Ready               Active              Leader              19.03.8
d85e6hmp2saf2xfyiq8nopvkp     rancher-worker1     Ready               Active                                  19.03.8
ccr3520glvgpyg7dn1zbkr8zg     rancher-worker2     Down                Active                                  19.03.8

Remove it from the manager
> docker node rm --force ccr3520glvgpyg7dn1zbkr8zg
ccr3520glvgpyg7dn1zbkr8zg

> docker node ls
ID                            HOSTNAME            STATUS              AVAILABILITY        MANAGER STATUS      ENGINE VERSION
st1b4xuylrj6mm5oggsk6hp04 *   rancher-home        Ready               Active              Leader              19.03.8
d85e6hmp2saf2xfyiq8nopvkp     rancher-worker1     Ready               Active                                  19.03.8

Manager and Deploy Service
Create a simple service
> docker service create --replicas 1 --name helloworld alpine ping docker.com
m45as37skje2gts6t6curew77
overall progress: 1 out of 1 tasks
1/1: running   [==================================================>]
verify: Service converged

List the service
>  docker service ls
ID                  NAME                MODE                REPLICAS            IMAGE               PORTS
m45as37skje2        helloworld          replicated          1/1                 alpine:latest

Check the detail
> docker service inspect --pretty helloworld
ID: m45as37skje2gts6t6curew77
Name: helloworld
Service Mode: Replicated
Replicas: 1
Placement:
UpdateConfig:
Parallelism: 1
On failure: pause
Monitoring Period: 5s
Max failure ratio: 0
Update order:      stop-first

List the server information
> docker service ps helloworld
ID                  NAME                IMAGE               NODE                DESIRED STATE       CURRENT STATE                ERROR               PORTS
vo5d6agsy1dw        helloworld.1        alpine:latest       rancher-home        Running             Running about a minute ago

Scale the service to 5
> docker service scale helloworld=5

List all the services
> docker service ps helloworld
ID                  NAME                IMAGE               NODE                DESIRED STATE       CURRENT STATE            ERROR                         PORTS
30nlrg5uu4c8        helloworld.1        alpine:latest       rancher-home        Running             Running 3 minutes ago                                 
vo5d6agsy1dw         \_ helloworld.1    alpine:latest       rancher-home        Shutdown            Failed 3 minutes ago     "task: non-zero exit (255)"  
fa9e3qlmcm47        helloworld.2        alpine:latest       rancher-worker2     Running             Running 30 seconds ago                                
8mr4dyaga779        helloworld.3        alpine:latest       rancher-worker1     Running             Running 29 seconds ago                                
7hbk7w99fo8z        helloworld.4        alpine:latest       rancher-worker1     Running             Running 29 seconds ago                                
0s7rbd9vwv3r        helloworld.5        alpine:latest       rancher-home        Running             Running 35 seconds ago 

Remove the service
> docker service rm helloworld

Run and Update the Tomcat Service
> docker service create --replicas 1 --name tomcat-service tomcat:8.5.8

Scale up to 2
> docker service scale tomcat-service=2

Rolling update to  tomcat:9.0.33
> docker service update --image tomcat:9.0.33 tomcat-service

Check status
> service ps tomcat-service
ID                  NAME                   IMAGE               NODE                DESIRED STATE       CURRENT STATE                 ERROR               PORTS
tei2ojnu7jxk        tomcat-service.1       tomcat:9.0.33       rancher-worker2     Running             Running 33 seconds ago                           
p6fg4k7l2jie         \_ tomcat-service.1   tomcat:8.5.8        rancher-worker2     Shutdown            Shutdown 53 seconds ago                          
q2it5kmfvois        tomcat-service.2       tomcat:9.0.33       rancher-home        Running             Running 55 seconds ago                           
e3dnf70mx0km         \_ tomcat-service.2   tomcat:8.5.8        rancher-home        Shutdown            Shutdown about a minute ago                      
r5kvdoruqdcf        tomcat-service.3       tomcat:9.0.33       rancher-worker1     Running             Running about a minute ago                       
33j1j47rk4pn         \_ tomcat-service.3   tomcat:8.5.8        rancher-worker1     Shutdown            Shutdown about a minute ago

Only see 3 history
> docker swarm update --task-history-limit 3


References:
https://yq.aliyun.com/articles/225511
https://outmanzzq.github.io/2019/06/14/portainer-for-docker-swarm/
https://note.qidong.name/2018/11/docker-swarm/
https://www.jianshu.com/p/df744c4e375e
https://github.com/jasonGeng88/blog/blob/master/201704/docker_swarm.md
https://stackoverflow.com/questions/41705134/how-can-i-remove-shutdown-docker-service-tasks-after-a-rolling-update

Maybe an useful tool
https://github.com/docker/machine