There are times when you need to stage your updates before updating all of your jobs. With blue/green updating, you can run one or more updated jobs and “stage” them before updating all of the running jobs. In this hands-on lab, you will use a blue/green method to perform job upgrades on running jobs in a controlled manner. You have been provided with a Nomad server in developer mode, where you will perform the tasks in this hands-on lab. The Nomad server has been configured with one server agent and one client agent, and Docker has been installed so that Nomad is ready to run jobs.
Successfully complete this lab by achieving the following learning objectives:
- Log in to the Provided Nomad Server
Log in to the server as "cloud_user" with the provided password to perform the tasks.
- Create, Modify, and Run a Job File Using the Blue/Green Method of Updates
Using the appropriate commands and the Nomad CLI, initialize a job file called example.nomad.
Modify the nomad file to use a blue/green method for updates.
Modify the job file to start two instances.
Submit the job to run, and wait until the job says it is healthy for all two instances.
- Change the Job File to Upgrade the Redis to Version 4
Edit the example.nomad file.
Change the version to be 4.0, and while the original job is running, submit the job to run.
Check if two jobs are running at the same time.
- Promote the Deployment
Check the status of the job. You should see it ask for a manual promotion, and there should be two canaries.
Promote the deployment for the updated version of Redis. You should see the promoted change to "true."