Previously, I have created a blog post about installing a lightweight blog using ghost and nginx.
For high availability and failover, place an ec2 instance to at least two different availability zones (such as one ec2 instance at ap-southeast-1b and one ec2 instance at ap-southeast-1a) using an auto-scaling group attached to an elastic load balancer.
If you are running your blog using this type of configuration, here are some tips to maintain your local docker image repository and keep it up to date. This also helps you to clean the old images that are pulled and locally stored. Old images or not used images consume local storage space such as ghost is 300MGB and each image will be the similar size. Better to ensure not to have any images stored in your ec2 volumes.
You can back-up the images to a tar file using below command:
docker save -o ghost.tar ghost
docker save -o ngnix.tar nginx
You can copy the files to your s3 bucket for backup
aws s3 cp ghost.tar s3://<bucketname>/ghost.tar
Ok. Now, pull the latest images from docker hub:
docker pull ghost
docker pull nginx
List the current docker images
It should give you a list of images stored locally as below:
So, at this list, Look at tag section for each image, latest tag is the updated version we just pulled from docker hub. Identify the image ID of the ones that are old or not used. If you haven't stopped the running container which is already using the image, you will not be able to remove the image just yet.
Stop the running containers:
docker stop blog
docker stop nginxserver
Remove the containers:
docker rm blog
docker rm nginxserver
Remove the unused images except the ones having the latest tag. (if you remove all containers when you execute the run command docker will pull the latest image by default)
docker rmi <imageID>
Run the containers with new images
docker run --name blog -p 2368:2368 -e NODE_ENV=production -v /home/ec2-user/dev/ghost/:/var/lib/ghost ghost -d
docker run -v /home/ec2-user/dev/ghost/Nginx/sites-enabled/:/etc/nginx/conf.d/ -v /home/ec2-user/dev/ghost/Nginx/certs/:/etc/nginx/certs -v /home/ec2-user/dev/ghost/Nginx/logs/:/var/log/nginx --name nginxserver -p 80:80 -d --link blog:blog nginx
Congratulations! you have just updated your blog to the latest version of ghost and nginx images.