Docker commit not saving changes (anapsix/webdis) - docker

Question

I started a docker images anapsix/webdis:
sudo docker run -d -p 7379:7379 -e LOCAL_REDIS=true anapsix/webdis
and changed the etc/webdis.json to allow websockets and committed it with
sudo docker commit <container-id>
however, when I used the new image to start a container, it does not keep the changes. Is there something I'm doing wrong?
Thanks!

Answer 1

In this case your problem is that the anapsix/webdis image has an entrypoint script (/entrypoint.sh) that generates /etc/webdis.json when the container starts.
Looking at the script, you can set the value of websockets by setting the WEBSOCKETS variable when you start the container:
docker run -d -p 7379:7379 \
-e LOCAL_REDIS=true \
-e WEBSOCKETS=true \
anapsix/webdis
When we run it like this, the generated /etc/webdis.json looks like:
{
"redis_host": "127.0.0.1",
"redis_port": 6379,
"redis_auth": null,
"http_host": "0.0.0.0",
"http_port": 7379,
"threads": 5,
"pool_size": 10,
"daemonize": false,
"websockets": true,
"database": 0,
"acl": [
{
"disabled": ["DEBUG", "FLUSHDB", "FLUSHALL"]
},
{
"http_basic_auth": "user:password",
"enabled": ["DEBUG"]
}
],
"verbosity": 8,
"logfile": "/dev/stdout"
}
More broadly, using docker commit is almost always the wrong thing to do; you should generate custom images using a Dockerfile (this gives you a much more manageable, reproducible process for creating container images).