docker-swarm-environment

The goal of this project is to have some examples deployed and running in a cluster of Docker Engines in swarm mode

Examples

• news-pipeline

• simple-service-keycloak-ldap

Prerequisite

• Docker
• docker-machine

Initializing a cluster of Docker Engines in swarm mode

In the following example, two Docker machines will be created. One will act as the Manager (Leader) and the another will be the Worker. The manager machine will be called manager1 and the worker machine, worker1. Those docker machines will act as nodes in our Docker Swarm.

The setup of the cluster can be done automatically or manually. All the commands below must be executed in a terminal.

Automatically

• Open a terminal and navigate to docker-swarm-environment root folder

• Run the following script

  ./setup-docker-swarm.sh
  

Manually

Open a terminal and follow the steps below

• Create Docker Machines

  • Run the command to create manager1 Docker Machine

    docker-machine create --driver virtualbox --virtualbox-memory 8192 manager1
    

  • Run the command to create worker1 Docker Machine

    docker-machine create --driver virtualbox --virtualbox-memory 8192 worker1
    

  • Check the status of all the Docker machines

    docker-machine ls
    

    You should see something similar to

    NAME       ACTIVE   DRIVER       STATE     URL                         SWARM   DOCKER     ERRORS
    manager1   -        virtualbox   Running   tcp://192.168.99.108:2376           v19.03.5
    worker1    -        virtualbox   Running   tcp://192.168.99.109:2376           v19.03.5
    

• Initialize a swarm

  • Export to MANAGER1_IP environment variable the ip address of the docker machine manager1

    export MANAGER1_IP=$(docker-machine ip manager1)
    

  • Create a new swarm

    docker-machine ssh manager1 docker swarm init --advertise-addr $MANAGER1_IP
    

  • Get the join-token for manager and worker. In case you want another node to join as a worker or as a manager, you must use those tokens

    export MANAGER_TOKEN=$(docker-machine ssh manager1 docker swarm join-token --quiet manager)
    export WORKER_TOKEN=$(docker-machine ssh manager1 docker swarm join-token --quiet worker)
    

  • Join to swarm worker1 as worker node.

    docker-machine ssh worker1 docker swarm join --token $WORKER_TOKEN $MANAGER1_IP:2377
    

• Create an overlay network

  docker-machine ssh manager1 docker network create --driver overlay --attachable my-swarm-net
  

View swarm members & info

• In a terminal, to view information about Swarm nodes run

  docker-machine ssh manager1 docker node ls
  

  It will prompt something like

  ID                            HOSTNAME            STATUS              AVAILABILITY        MANAGER STATUS      ENGINE VERSION
  60hh6m3rqqch60u7yza9lf6f5 *   manager1            Ready               Active              Leader              19.03.12
  21urc24cgvwq6vjwuizy1bnar     worker1             Ready               Active                                  19.03.12
  

• To see the current state and more information of the Swarm, run

  docker-machine ssh manager1 docker info
  

  The output will be similar to

  Client:
   Debug Mode: false
  
  Server:
   Containers: 0
    Running: 0
    Paused: 0
    Stopped: 0
   Images: 0
   Server Version: 19.03.12
   Storage Driver: overlay2
    Backing Filesystem: extfs
    Supports d_type: true
    Native Overlay Diff: true
   Logging Driver: json-file
   Cgroup Driver: cgroupfs
   Plugins:
    Volume: local
    Network: bridge host ipvlan macvlan null overlay
    Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog
   Swarm: active
    NodeID: 60hh6m3rqqch60u7yza9lf6f5
    Is Manager: true
    ClusterID: ocflb0g33nrvh79n85lob6lhc
    Managers: 1
    Nodes: 2
    Default Address Pool: 10.0.0.0/8
    SubnetSize: 24
    Data Path Port: 4789
    Orchestration:
     Task History Retention Limit: 5
    Raft:
     Snapshot Interval: 10000
     Number of Old Snapshots to Retain: 0
     Heartbeat Tick: 1
     Election Tick: 10
    Dispatcher:
     Heartbeat Period: 5 seconds
    CA Configuration:
     Expiry Duration: 3 months
     Force Rotate: 0
    Autolock Managers: false
    Root Rotation In Progress: false
    Node Address: 192.168.99.120
    Manager Addresses:
     192.168.99.120:2377
   Runtimes: runc
   Default Runtime: runc
   Init Binary: docker-init
   containerd version: 7ad184331fa3e55e52b890ea95e65ba581ae3429
   runc version: dc9208a3303feef5b3839f4323d9beb36df0a9dd
   init version: fec3683
   Security Options:
    seccomp
     Profile: default
   Kernel Version: 4.19.130-boot2docker
   Operating System: Boot2Docker 19.03.12 (TCL 10.1)
   OSType: linux
   Architecture: x86_64
   CPUs: 1
   Total Memory: 7.79GiB
   Name: manager1
   ID: XAYV:H4TN:VI2S:D22T:PISE:G6QA:WMXJ:YKYB:QRBV:7ZXB:IRB3:XEM5
   Docker Root Dir: /mnt/sda1/var/lib/docker
   Debug Mode: false
   Registry: https://index.docker.io/v1/
   Labels:
    provider=virtualbox
   Experimental: false
   Insecure Registries:
    127.0.0.0/8
   Live Restore Enabled: false
   Product License: Community Engine
  

Cleaning up

In a terminal, run the command below o remove manager1 and worker1 docker machines

docker-machine rm worker1 manager1

Issues

Unable to upgrade this project because, while running setup-docker-swarm.sh script, I am getting the following error while creating manager1 and worker1

Error creating machine: Error checking the host: Error checking and/or regenerating the certs: There was an error validating certificates for host "192.168.99.132:2376": dial tcp 192.168.99.132:2376: i/o timeout

Besides, after the script finishes, I cannot access docker-daemon from manager1 and worker1 machines

$ eval $(docker-machine env manager1)
Error checking TLS connection: Error checking and/or regenerating the certs: There was an error validating certificates for host "192.168.99.131:2376": dial tcp 192.168.99.131:2376: i/o timeout
You can attempt to regenerate them using 'docker-machine regenerate-certs [name]'.
Be advised that this will trigger a Docker daemon restart which might stop running containers.