How to update a container? What did I miss?

[ghabxph]

The question might be dumb, but I like to ask: How to update a container?

Here's my scenario.
I have a container called: ecred/ecred-home
https://hub.docker.com/r/ecred/ecred-home

And I only have one tag: latest.

I have an assumption that when I will run watchtower, it'll check running containers, and look for update on each image that is running

# After this, I assume that watchtower will check for each container for updates / changes in tag.
docker run -d \
    --name watchtower \
    -v /var/run/docker.sock:/var/run/docker.sock \
    containrrr/watchtower

Upon checking, the expected container was still not updating. What did I miss?

ghabxph@manjaro ~> date
Tuesday, 05 January, 2021 09:04:20 PM PST
ghabxph@manjaro ~> docker ps
CONTAINER ID        IMAGE                   COMMAND                  CREATED             STATUS           PORTS                    NAMES
0022657f925b        containrrr/watchtower   "/watchtower"            21 minutes ago      Up 21 minutes    8080/tcp                 watchtower
2ee8531c9c78        ecred/ecred-home        "/docker-entrypoint.…"   26 minutes ago      Up 26 minutes    0.0.0.0:1314->80/tcp     ecred-home_app_1
ghabxph@manjaro ~> date
Tuesday, 05 January, 2021 09:16:10 PM PST
ghabxph@manjaro ~>  docker ps
CONTAINER ID        IMAGE                   COMMAND                  CREATED             STATUS           PORTS                    NAMES
0022657f925b        containrrr/watchtower   "/watchtower"            33 minutes ago      Up 33 minutes    8080/tcp                 watchtower
2ee8531c9c78        ecred/ecred-home        "/docker-entrypoint.…"   38 minutes ago      Up 38 minutes    0.0.0.0:1314->80/tcp     ecred-home_app_1

[zoispag]

If you want the update to happen right away and the turn watchtower off, you need to pass the --run-once flag.
The interval is by default 24hours in the latest version, due to changes to Dockerhub.

You can either set your own shorter interval, or just run it using the --run-once flag.