8. Swarm creates maintenance and horizontal extension service

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establish service

docker service create --name demo busybox sh -c "while true;do sleep 3600;done"

see service, There is only one copy replicas 1/1

docker service ls
ID                  NAME                MODE                REPLICAS            IMAGE               PORTS
qbpicc7rvm49        demo                replicated          1/1                 busybox:latest 

see service Details

docker service ps demo
ID                  NAME                IMAGE               NODE                    DESIRED STATE       CURRENT STATE                ERROR               PORTS
nlgymox7pt59        demo.1              busybox:latest      localhost.localdomain   Running             Running about a minute ago 

Set up service Replications for 5

docker service scale demo=5

Look again service, Number of copies replicas 5/5

docker service ls
ID                  NAME                MODE                REPLICAS            IMAGE               PORTS
qbpicc7rvm49        demo                replicated          5/5                 busybox:latest  

It turns on 5 individual service copy , Distribution in 3 individual worker node On

docker service ps demo
ID                  NAME                IMAGE               NODE                    DESIRED STATE       CURRENT STATE            ERROR                              PORTS
nlgymox7pt59        demo.1              busybox:latest      localhost.localdomain   Running             Running 6 minutes ago                                       
wjnahehppsvu        demo.2              busybox:latest      localhost.localdomain   Running             Running 2 minutes ago
ogojxvke7t9b        demo.3              busybox:latest      localhost.localdomain   Running             Running 3 minutes ago                                       
dweehxcozoku        demo.4              busybox:latest      localhost.localdomain   Running             Running 2 minutes ago
1ix2fdj39m03        demo.5              busybox:latest      localhost.localdomain   Running             Running 2 minutes ago

Let's go to one of them worker node Delete one from the service copy

docker ps
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS               NAMES
a8661d168e78        busybox:latest      "sh -c 'while true;d…"   4 minutes ago       Up 4 minutes                            demo.3.ogojxvke7t9bza62haisw3as2
2f800599e183        busybox:latest      "sh -c 'while true;d…"   8 minutes ago       Up 8 minutes                            demo.1.nlgymox7pt59vrdj7lfjk8e4b

docker rm -f 2f800599e183

CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS               NAMES
a8661d168e78        busybox:latest      "sh -c 'while true;d…"   38 minutes ago      Up 38 minutes                           demo.3.ogojxvke7t9bza62haisw3as2

And then back to swarm manager Node , see service The number of copies becomes 4 individual , But after a short time , Back to 5 individual

docker service ls
ID                  NAME                MODE                REPLICAS            IMAGE               PORTS
qbpicc7rvm49        demo                replicated          5/5                 busybox:latest 

Check it again demo Copy details ,demo.1 It was deleted , But in swarm manager Under the management of , Some workder node Another one has been opened service Copy of , Guarantee service The number of copies of is valid .

docker service ps demo
ID                  NAME                IMAGE               NODE                    DESIRED STATE       CURRENT STATE             ERROR                              PORTS
z5vhrcrec1d4        demo.1              busybox:latest      localhost.localdomain   Running             Running 6 minutes ago
nlgymox7pt59         \_ demo.1          busybox:latest      localhost.localdomain   Shutdown            Failed 6 minutes ago      "task: non-zero exit (137)"         
wjnahehppsvu        demo.2              busybox:latest      localhost.localdomain   Running             Running 44 minutes ago   
ogojxvke7t9b        demo.3              busybox:latest      localhost.localdomain   Running             Running 44 minutes ago                                       
dweehxcozoku        demo.4              busybox:latest      localhost.localdomain   Running             Running 44 minutes ago 
1ix2fdj39m03        demo.5              busybox:latest      localhost.localdomain   Running             Running 44 minutes ago          

We want to delete service, Need to be in swarm manager Node

docker service rm demo
demo

docker service ls
ID                  NAME                MODE                REPLICAS            IMAGE               PORTS