using localhost or a permanent address

[MichaelLSmith]

Whenever I start my containers up, I see this message:

AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 172.18.0.2. Set the 'ServerName' directive globally to suppress this message

How and where do I set the ServerName directive so that it's a permanent address? Can I set it so that it's localhost?

[yosifkit]

The message is just a warning and shouldn't have any effect on serving WordPress.

[MichaelLSmith]

My problem is that it changes almost every time I start up docker. I was hoping to set it to be the same address every time. It seems to fluctuate between 172.18.0.2 and 172.18.0.3. When it's .2 I can navigate to the site, but when it's .3, after I enter the address in my browser, it always tries to .2.

[yosifkit]

Yes, Docker will assign the next IP address available in the block that it uses. WordPress redirects to whatever URL you first used to access it. You can change the site url.

I find the simplest solution for local development on WordPress is to set a -p 80:80 on the docker run and add a hostname alias for localhost, like example.com, to /etc/hosts on the docker host and then I can access in the browser under that alias of example.com.

It is also possible to assign a static IP to a container: http://stackoverflow.com/a/35359185

[SamMorrowDrums]

The idea with Docker is that you can deploy lots of versions of the same thing, so setting the site url to localhost (or custom host as @yosifkit suggests) is what you would do.

Also, it seems unusual that you would use the docker adaptor URL. Why don't you expose 0.0.0.0::80 when you start the container (replace with a port like 3000)

Then it should always be available as localhost:<port> ex. localhost:3000.

[tianon]

I'm going to close this, since this is Docker and WordPress both working exactly the way they're designed to (and I think there's some good discussion here about the issue -- feel free to continue the discussion if you feel it isn't clear).

I will note that the way I usually solve this for my own deployments of WordPress is by using NGINX in front of the WordPress container to normalize the external endpoint (especially since I usually host several other things on the same server).