Docker Mastery: Section 9 - Service Updates: Changing things in flight

• section9-79

Udemy

• Docker Mastery: with Kubernetes +Swarm from a Docker Captain

• GitHub: udemy-docker-mastery

• 講師的YouTube

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Service Updates

• Provides rolling replacement of tasks/containers in a service
• Limits downtime (be careful with prevents downtime)
  • TEST EARLY + TEST OFTEN
• Will replace containers for most changes
• Has many, many cli options to control the update
• Create options will usually change, adding -add or -rm to them
• Includes roolback and healthcheck options
• Also has scale & rollback subcommand for quicker access
  • docker service scale web=4 and docker service rollback web
• A stack deploy, when pre-existing, will issue service updates

Swarm Update Examples

• Just update the image used to a newer version
  • docker service update --image myapp:1.2.1 <servicename>
• Adding an environment variable and remove a port
  • dokcer service update --env-add NODE_ENV=production --publish-rm 8080
• Change unmber of replicas of two services
  • docker service scale web=8 api=6

Swarm Updates in Stack Files

• Same command. Just edit the YAML file, then
  • docker stack deploy -c file.yml <stackname>

開始 Example

• docker service create -p 8080:80 --name web nginx:1.13.7

      PS E:\Udemy\Docker Mastery\udemy-docker-mastery\swarm-stack-3> docker service create -p 8080:80 --name web nginx:1.13.7
      1rz9tan5xjtjyyuwwleympbt3
      overall progress: 1 out of 1 tasks                                                  
      1/1: running                                                                             
      verify: Service converged     
  

• Servcie scale
  • docker service scale web=5

   PS E:\Udemy\Docker Mastery\udemy-docker-mastery\swarm-stack-3> docker service scale web=5
   web scaled to 5
   overall progress: 5 out of 5 tasks                                                                      
   1/5: running                                                                                            
   2/5: running                                                                                            
   3/5: running                                                                                            
   4/5: running                                                                                            
   5/5: running                                                                                            
   verify: Service converged   
  

• Service update
  • docker servcie update --image nginx:1.13.6 web
  • 把舊的刪掉 –> 建新的 –> 都ok –> 繼續

   PS E:\Udemy\Docker Mastery\udemy-docker-mastery\swarm-stack-3> docker service update --image nginx:1.13.6 web
   web
   overall progress: 5 out of 5 tasks                                                                      
   1/5: running                                                                                            
   2/5: running                                                                                            
   3/5: running                                                                                            
   4/5: running                                                                                            
   5/5: running                                                                                            
   verify: Service converged  
  

• Chnage publish port
  • add and rm at the same time
  • docker service update --publish-rm 8080 --publish-add 9090:80 web

   PS E:\Udemy\Docker Mastery\udemy-docker-mastery\swarm-stack-3> docker service update --publish-rm 8080 --publish-add 9090:80 web
   web
   overall progress: 5 out of 5 tasks                                                                      
   1/5: running                                                                                            
   2/5: running                                                                                            
   3/5: running                                                                                            
   4/5: running                                                                                            
   5/5: running                                                                                            
   verify: Service converged  
  

• Docker tips
  • 優化 swarm 分配 node
  • docker service update --force web

   PS E:\Udemy\Docker Mastery\udemy-docker-mastery\swarm-stack-3> docker service update --force web
   web
   overall progress: 5 out of 5 tasks                                                                      
   1/5: running                                                                                            
   2/5: running                                                                                            
   3/5: running                                                                                            
   4/5: running                                                                                            
   5/5: running                                                                                            
   verify: Service converged  
  

• Examples Cleanup
  • docker service rm web

      PS E:\Udemy\Docker Mastery\udemy-docker-mastery\swarm-stack-3> docker service rm web
      web