-
Prepare three virtual machines, corresponding network conditions are as follows:
IP address host name Effect 172.18.74.26 manager Management Node 172.18.74.29 g160402 worker 172.18.74.25 u180402 worker Modify the host name according to the above conditions and add the parsing configuration of the other two nodes to / etc/hosts
-
Change the docker daemon listening mode of all nodes to 0.0.0.0:2375
-
Configuration I
#Modify the line [service] ExecStart as follows example@manager:~$ sudo vi /lib/systemd/system/docker.service ExecStart=/usr/bin/dockerd -H 0.0.0.0:2375 -H unix:///var/run/docker.sock example@manager:~$ sudo systemctl daemon-reload example@manager:~$ sudo systemctl restart docker
-
Configuration II
example@u180402:~$ cat /etc/docker/daemon.json { "registry-mirrors": [ "https://reg-mirror.qiniu.com", "https://hub-mirror.c.163.com", "https://registry.aliyuncs.com" ], "hosts" : ["unix:///var/run/docker.sock", "tcp://0.0.0.0:2375"] } example@manager:~$ sudo vi /lib/systemd/system/docker.service ExecStart=/usr/bin/dockerd example@manager:~$ sudo systemctl daemon-reload example@manager:~$ sudo systemctl restart docker
-
-
Initialization Cluster
-
Create management nodes
example@manager:~$ docker swarm init --advertise-addr 172.18.74.26 Swarm initialized: current node (w78pv2cxmucv2vca3v5r069wt) is now a manager. To add a worker to this swarm, run the following command: docker swarm join --token SWMTKN-1-1fffxrlpybn1oz0qsff9ywxuz7ef1o7v6c4qqf6kwvckt6bphi-6t9lfyat23n99do5y9mpdtdkg 192.168.1.154:2377 To add a manager to this swarm, run 'docker swarm join-token manager' and follow the instructions. -
After initializing the management node, two new network docker_gwbridge, ingress are created
example@manager:~$ docker network ls NETWORK ID NAME DRIVER SCOPE 6b3877ce1c6f bridge bridge local 6f5af407c445 docker_gwbridge bridge local 25066e8c0d9e host host local p5dq2m8snezx ingress overlay swarm b512147e5000 none null local
- bridge is the default network created by docker and exists in all docker containers. The docker engine automatically creates subnetworks and routes, and the docker run command automatically adds new containers to the network.
- docker_gwbridge is a swarm node communication network created automatically by nodes joining swarm.
- Overlay cross-host network is available only to nodes in swarm that need to be served. When you create a service using overlay network, the management node automatically extends the overlay network to the node running the service task.
-
node nodes join the cluster
#g160402 example@g160402:~$ docker swarm join --token SWMTKN-1-1fffxrlpybn1oz0qsff9ywxuz7ef1o7v6c4qqf6kwvckt6bphi-6t9lfyat23n99do5y9mpdtdkg 172.18.74.26:2377 This node joined a swarm as a worker. #u180402 example@u180402:~$ docker swarm join --token SWMTKN-1-1fffxrlpybn1oz0qsff9ywxuz7ef1o7v6c4qqf6kwvckt6bphi-6t9lfyat23n99do5y9mpdtdkg 172.18.74.26:2377 This node joined a swarm as a worker.
-
Manage Node View Node Status
- Active: The scheduler can schedule tasks to that node
- Pause: The scheduler cannot schedule tasks to the node, but existing tasks will continue to run
- Drain: The scheduler cannot schedule tasks to that node and stops existing tasks and assigns them to other Active state nodes
example@manager:~$ docker node ls ID HOSTNAME STATUS AVAILABILITY MANAGER STATUS ENGINE VERSION vrfif1jr3v0gl29o8okhdlc4l g160402 Ready Active 18.06.1-ce w78pv2cxmucv2vca3v5r069wt * manager Ready Active Leader 18.09.5 7jjv186tvj8hscubg6me026vq u180402 Ready Active 18.06.1-ce -
Withdrawal from Cluster
example@u180402:~$ docker swarm leave Node left the swarm. example@g160402:~$ docker swarm leave Node left the swarm. ID HOSTNAME STATUS AVAILABILITY MANAGER STATUS ENGINE VERSION vrfif1jr3v0gl29o8okhdlc4l g160402 Down Active 18.06.1-ce w78pv2cxmucv2vca3v5r069wt * manager Ready Active Leader 18.09.5 7jjv186tvj8hscubg6me026vq u180402 Down Active 18.06.1-ce #Mandatory Exit of Cluster by manager example@manager:~$ docker swarm leave --force Node left the swarm.
-
-
Enabling services in clusters
-
Create an http service with two copies
example@manager:~$ docker service create --replicas 2 --name hello-swarm httpd:latest 01voy53c0ygxb5w7ncocxwfvp overall progress: 2 out of 2 tasks 1/2: running [==================================================>] 2/2: running [==================================================>] verify: Service converged example@manager:~$ docker service ls ID NAME MODE REPLICAS IMAGE PORTS 01voy53c0ygx hello-swarm replicated 2/2 httpd:latest example@manager:~$ docker service ps hello-swarm ID NAME IMAGE NODE DESIRED STATE CURRENT STATE ERROR PORTS qw0rfrbhgk5v hello-swarm.1 httpd:latest manager Running Running about a minute ago byhnp23chffg hello-swarm.2 httpd:latest g160402 Running Running about a minute ago example@g160402:~$ docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES f9f928c906e4 httpd:latest "httpd-foreground" 2 minutes ago Up 2 minutes 80/tcp hello-swarm.2.byhnp23chffg59hbnpdndgp69
-
Update service configuration
- Increase port mapping
example@manager:~$ docker service update --publish-add 8080:80 hello-swarm hello-swarm overall progress: 2 out of 2 tasks 1/2: running [==================================================>] 2/2: running [==================================================>] verify: Service converged example@g160402:~$ docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 8ed735b92841 httpd:latest "httpd-foreground" 13 seconds ago Up 11 seconds 80/tcp hello-swarm.2.0v51ok3f424iaziisc51tfq00
At this time, you can see the successful "It works" interface of httpd when browser accesses port 8080 of any server.
-
Cluster Expansion
enee@manager:~$ docker service scale hello-swarm=4 hello-swarm scaled to 4 overall progress: 4 out of 4 tasks 1/4: running [==================================================>] 2/4: running [==================================================>] 3/4: running [==================================================>] 4/4: running [==================================================>] enee@manager:~$ docker service ps hello-swarm ID NAME IMAGE NODE DESIRED STATE CURRENT STATE ERROR PORTS 3o6rzluek155 hello-swarm.1 httpd:latest u180402 Running Running 5 minutes ago qw0rfrbhgk5v \_ hello-swarm.1 httpd:latest manager Shutdown Shutdown 6 minutes ago 0v51ok3f424i hello-swarm.2 httpd:latest g160402 Running Running 6 minutes ago byhnp23chffg \_ hello-swarm.2 httpd:latest g160402 Shutdown Shutdown 6 minutes ago faitccodd7vq hello-swarm.3 httpd:latest manager Running Running 27 seconds ago biqpebevezkj hello-swarm.4 httpd:latest manager Running Running 26 seconds ago
At this time, the manager server runs two http services, u1804021 and g1604021.
-
Add directory mapping for services, refresh pages many times, and access services will be randomly distributed in the running containers.
example@manager:~$ docker service update --mount-add type=bind,source=/home/example/temp/,destination=/usr/local/apache2/htdocs/ hello-swarm hello-swarm overall progress: 2 out of 2 tasks 1/2: running [==================================================>] 2/2: running [==================================================>] verify: Service converged
-
Restart the service without changing any configuration
example@g160402:~$ docker service update --force hello-swarm hello-swarm overall progress: 2 out of 2 tasks 1/2: running [==================================================>] 2/2: running [==================================================>] verify: Service converged example@g160402:~$ docker service ps hello-swarm ID NAME IMAGE NODE DESIRED STATE CURRENT STATE ERROR PORTS x0j4ow0jozso hello-swarm.1 httpd:latest g160402 Running Running 2 minutes ago b8g0xoo53w4a \_ hello-swarm.1 httpd:latest g160402 Shutdown Shutdown 2 minutes ago q8l75pkn9r3x hello-swarm.2 httpd:latest g160402 Running Running 2 minutes ago q28kvehhdcun \_ hello-swarm.2 httpd:latest g160402 Shutdown Shutdown 2 minutes ago 6nvq8ntrfs04 \_ hello-swarm.2 httpd:latest g160402 Shutdown Failed 20 minutes ago "task: non-zero exit (137)" example@g160402:~$ docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 36fd1a6c3b28 httpd:latest "httpd-foreground" About a minute ago Up About a minute 80/tcp hello-swarm.1.x0j4ow0jozsomdxnnw5vkcv6s 6c4501017beb httpd:latest "httpd-foreground" About a minute ago Up About a minute 80/tcp hello-swarm.2.q8l75pkn9r3xy33g28llgzui5
-
Delete service
example@manager:~$ docker service rm hello-swarm hello-swarm
-
-
Let the service run on the specified node
-
Add labels for each node
-
Use the command line to add and delete
example@manager:~$ docker node update --label-add role=manager manager manager example@manager:~$ docker node update --label-add role=worker1 g160402 g160402 example@manager:~$ docker node update --label-add role=worker2 u180402 example@manager:~$ docker node inspect g160402 ...... "Spec": { "Labels": { "role": "worker1" }, ...... #Delete Node Labels example@manager:~$ docker node update --label-rm role g160402 g160402
-
Add tags to docker-daemon
example@manager:~$ sudo vi /lib/systemd/system/docker.service ExecStart=/usr/bin/dockerd -H 0.0.0.0:2375 -H unix:///var/run/docker.sock --label hostname=manage
-
-
Specify Running Node
example@manager:~$ docker service create --replicas 2 --constraint 'node.labels.role == worker1' --name hello-swarm httpd:latest rfz6aocpi9bh4foq4wzw1bl3x overall progress: 2 out of 2 tasks 1/2: running [==================================================>] 2/2: running [==================================================>] verify: Service converged example@g160402:~$ docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES b098a29fc83b httpd:latest "httpd-foreground" 7 seconds ago Up 6 seconds 80/tcp hello-swarm.1.b8g0xoo53w4adyvf9mdl1hozd d2cfd7a650c3 httpd:latest "httpd-foreground" 7 seconds ago Up 6 seconds 80/tcp hello-swarm.2.6nvq8ntrfs04i1mx0wiy5f92h
-
-
After the container exits or deletes abnormally, the manager node starts the new service again and records the exit log.
example@manager:~$ docker service ps hello-swarm ID NAME IMAGE NODE DESIRED STATE CURRENT STATE ERROR PORTS b8g0xoo53w4a hello-swarm.1 httpd:latest g160402 Running Running 4 minutes ago 6nvq8ntrfs04 hello-swarm.2 httpd:latest g160402 Running Running 4 minutes ago example@g160402:~$ docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES b098a29fc83b httpd:latest "httpd-foreground" 3 minutes ago Up 3 minutes 80/tcp hello-swarm.1.b8g0xoo53w4adyvf9mdl1hozd d2cfd7a650c3 httpd:latest "httpd-foreground" 3 minutes ago Up 3 minutes 80/tcp hello-swarm.2.6nvq8ntrfs04i1mx0wiy5f92h example@g160402:~$ docker rm -f d2cfd7a650c3 d2cfd7a650c3 example@g160402:~$ docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES b098a29fc83b httpd:latest "httpd-foreground" 4 minutes ago Up 4 minutes 80/tcp hello-swarm.1.b8g0xoo53w4adyvf9mdl1hozd example@manager:~$ docker service ps hello-swarm ID NAME IMAGE NODE DESIRED STATE CURRENT STATE ERROR PORTS b8g0xoo53w4a hello-swarm.1 httpd:latest g160402 Running Running 5 minutes ago q28kvehhdcun hello-swarm.2 httpd:latest g160402 Running Running 7 seconds ago 6nvq8ntrfs04 \_ hello-swarm.2 httpd:latest g160402 Shutdown Failed 13 seconds ago "task: non-zero exit (137)" example@g160402:~$ docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES d35b717ddc46 httpd:latest "httpd-foreground" 19 seconds ago Up 14 seconds 80/tcp hello-swarm.2.q28kvehhdcunpi3h5e4a12679 b098a29fc83b httpd:latest "httpd-foreground" 5 minutes ago Up 5 minutes 80/tcp hello-swarm.1.b8g0xoo53w4adyvf9mdl1hozd
-
Node Upgrade and Degradation
-
"MANAGER STATUS" status statement:
- Leader: The primary manager node that makes all group management and orchestration decisions for a group
- Reachable: If the Leader node becomes unavailable, it is eligible to be elected as a new Leader
- Unavailable: This node does not have any connection with other Manager nodes. In this case, a new Manager node should be added to the cluster, or a Worker node should be promoted to a Manager node.
-
Upgrade the g160402 node so that the node can execute the executable command of the manager node, "MANAGER STATUS" becomes "Reachable"
example@manager:~$ docker node promote g160402 u180402 Node g160402 promoted to a manager in the swarm. Node u180402 promoted to a manager in the swarm. example@g160402:~$ docker node ls ID HOSTNAME STATUS AVAILABILITY MANAGER STATUS ENGINE VERSION kl6siwciwca88y6sp8mhku38p * g160402 Ready Active Reachable 18.06.1-ce uyoiijq9vtdi9f6tvkr4wuqh9 manager Ready Active Leader 18.09.5 ffm3ttsc31l4tiwa4lyu7vol4 u180402 Ready Active 18.06.1-ce example@g160402:~$ docker node ls ID HOSTNAME STATUS AVAILABILITY MANAGER STATUS ENGINE VERSION kl6siwciwca88y6sp8mhku38p * g160402 Ready Active Leader 18.06.1-ce uyoiijq9vtdi9f6tvkr4wuqh9 manager Unknown Active Unreachable 18.09.5 ffm3ttsc31l4tiwa4lyu7vol4 u180402 Ready Active Reachable 18.06.1-ce
-
Node Degradation
example@manager:~$ docker node demote g160402 Manager g160402 demoted in the swarm. example@manager:~$ docker node ls ID HOSTNAME STATUS AVAILABILITY MANAGER STATUS ENGINE VERSION kl6siwciwca88y6sp8mhku38p g160402 Ready Active 18.06.1-ce uyoiijq9vtdi9f6tvkr4wuqh9 * manager Ready Active Leader 18.09.5 ffm3ttsc31l4tiwa4lyu7vol4 u180402 Ready Active 18.06.1-ce
-
-
Docker stack
-
Instruction usage
parameter Explain deploy Create or update a stack ls List existing stacks ps List tasks on the stack rm Delete one or more stacks services List the services in the stack -
Start a service
example@manager:/data/@stack/giot$ pwd /data/@stack/giot example@manager:/data/@stack/giot$ ls docker-compose.yml #Create a custom network example@manager:~/docker$ docker network create --driver overlay giot_network 7sfjbimchcmhh1336v075y4d9 example@manager:/data/@stack/giot$ cat docker-compose.yml version: "3" services: nginx: image: nginx:1.15.8-alpine deploy: replicas: 2 resources: limits: cpus: "0.1" memory: 50M placement: constraints: - node.labels.role == worker1 restart_policy: condition: on-failure ports: - 80:80/tcp volumes: - /data/containers/nginx/etc/nginx/nginx.conf:/etc/nginx/nginx.conf:ro - /data/containers/nginx/etc/nginx/conf.d:/etc/nginx/conf.d - /dev/log:/dev/log - /var/log/nginx:/var/log/nginx - /data:/data - /etc/localtime:/etc/localtime:ro networks: - giot_network networks: giot_network: external: true example@manager:/data/@stack/giot$ docker stack deploy -c docker-compose.yml giot Creating network giot_default Creating service giot_nginx example@g160402:/data/containers/nginx$ docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES b7b8f7d57a24 nginx:1.15.8-alpine "nginx -g 'daemon of..." 9 seconds ago Up 7 seconds 80/tcp test_nginx.1.x9262cydwiwr6au792z3m39xg be5b8aae70ee nginx:1.15.8-alpine "nginx -g 'daemon of..." 9 seconds ago Up 7 seconds 80/tcp test_nginx.2.uf5s1xi537h6k6qkea5wunu3m
-
Appendix 1: docker service parameter list
| Abbreviation | parameter | Parameter type | describe | Default values |
|---|---|---|---|---|
| –config | config | Configuration assigned to services | ||
| –constraint | list | constraint condition | ||
| –container-label | list | Container label | ||
| –credential-spec | credential-spec | Credential Specification for Hosted Service Accounts (Windows Limited) | ||
| -d | –detach | Exit immediately, not wait for convergence of services | ||
| –dns | list | Setting up custom DNS servers | ||
| –dns-option | list | Setting DNS parameters | ||
| –dns-search | list | Setting up custom DNS search fields | ||
| –endpoint-mode | string | Endpoint mode (vip or dnsrr) | vip | |
| –entrypoint | command | Overlay mirror default ENTRYPOINT | ||
| -e | –env | list | Setting environment variables | |
| –env-file | list | Read environment variables from files | ||
| –generic-resource | list | User-defined resources | ||
| –group | list | Setting up one or more different user groups for containers | ||
| –health-cmd | string | The command line for checking health | ||
| –health-interval | duration | Time interval of health examination (m s/s/m/h) | ||
| –health-retries | int | Reporting unhealthy successive failures | ||
| –health-start-period | duration | The time of container initialization (m s/s/m/h) before recounting to instability | ||
| –health-timeout | duration | Maximum permissible time for a check (m s/s/m/h) | ||
| –host | list | Set one or more host-to-IP mappings (host:ip) | ||
| –hostname | string | Container host name | ||
| –isolation | string | Service Container Isolation Mode | ||
| -l | –label | list | Service label | |
| –limit-cpu | decimal | CPUs limitation | ||
| –limit-memory | bytes | Memory limitation | ||
| –log-driver | string | Log Driver for Services | ||
| –log-opt | list | Log Driver Parameters | ||
| –mode | string | Service pattern (replicated or global) | replicated | |
| –mount | mount | Mount the file system to the service | ||
| –name | string | Service Name | ||
| –network | network | service network | ||
| –no-healthcheck | Disable any health checks specified in containers | |||
| –no-resolve-image | Do not query the registry to resolve image summaries and support platforms | |||
| –placement-pref | pref | Adding preference settings | ||
| -p | –publish | port | Publish a port as a node port | |
| -q | –quiet | Simplify progress output | ||
| –read-only | Mount the root file system of the container as read-only | |||
| –replicas | uint | Number of tasks (i.e. number of container replicas) | 1 | |
| –reserve-cpu | decimal | Keep CPUs | ||
| –reserve-memory | bytes | Retain memory | ||
| –restart-condition | string | Restart conditions ("none", "on-failure", "any") | any | |
| –restart-delay | duration | Restart delay (ns/us/m s/s/m/h) | 5s | |
| –restart-max-attempts | uint | Maximum number of restarts before abandonment | ||
| –restart-window | duration | Windows for evaluating restart policies (ns/us/m s/s/m/h) | ||
| –rollback-delay | duration | Task rollback delay (ns/us/m s/s/m/h) | 0s | |
| –rollback-failure-action | string | Roll back failed operations ("pause", "continue") | pause | |
| –rollback-max-failure-ratio | float | Fault rate tolerated during rollback | 0 | |
| –rollback-monitor | duration | Duration of each task after rollback to monitor failure (ns/us/m s/s/m/h) | 5s | |
| –rollback-order | string | Rollback order ("start-first"/"stop-first") | stop-first | |
| –rollback-parallelism | uint | Maximum number of tasks rolled back at the same time (0 means rollback all at the same time) | 1 | |
| –secret | secret | Security mechanisms assigned to services | ||
| –stop-grace-period | duration | The waiting time before ending a container (ns/us/m s/s/m/h) | 10s | |
| –stop-signal | string | Stop container signal | ||
| -t | –tty | Assign a pseudo-TTY | ||
| –update-delay | duration | Update latency (ns/us/m s/s/m/h) | 0s | |
| –update-failure-action | string | Update failed actions ("pause", "continue", "rollback") | pause | |
| –update-max-failure-ratio | float | Failure rate tolerated during updates | 0 | |
| –update-monitor | duration | Duration of each task update to monitor failure (ns/us/m s/s/m/h) | 5s | |
| –update-order | string | Update order ("start-first", "stop-first") | stop-first | |
| –update-parallelism | uint | Maximum number of tasks updated at the same time (0 represents all updates at the same time) | 1 | |
| -u | –user | string | Username or UID (format: <name/uid>[: <group/gid>]) | |
| –with-registry-auth | Send authentication information to Swarm agent | |||
| -w | –workdir | string | Working catalogue in container |