The policy has always been to only release for supported versions of operating systems, so this change aligns what we release for and how Dokku may be installed.
Folks running unmaintained operating systems should upgrade, as the packages are never guaranteed to exist in the Dokku apt repository.
Several of the packages being installed were actually transitional packages, that is, the package itself is either a complete no-op (since the package is already installed), or else the package only exists to depend on another package of a new name (to support people who are running older operating systems).
For the former, we can drop the dependency entirely, and for the latter we should use the new package name directly.
The shorthand is more prevalent in this codebase, and is something that bash supports, so we should just use the same thing everywhere.
Note that we do not use shorthand redirect in Makefile as shell parsing is a bit different in Make and the shorthand redirect doesn't seem to be properly supported, causing CI errors.
This makes standard use of shellcheck work without needing to provide extra configuration anywhere.
Also remove use of inline 'shellcheck disable' calls that are already defined in the .shellcheckrc and don't need to be set inline.
While we will still build for 18.04, we will now stop testing against it. Instead, we will test against 20.04, the next EOL release after 18.04.
Once Ubuntu 18.04 is EOL, any references to it will also be removed.
Note that 18.04 support was already deprecated in Dokku 0.28.0, so this change is just acknowledging that deprecation.
We will no longer support CentOS, Fedora, and Opensuse as installation targets. These are not actively maintained by anyone with commit rights and occasionally cause issues for users as they are not tested during the release process.
Rather than have subpar support for an untested operating system, we're removing support for them completely. Users of these operating systems should take a look migration to the docker-based installation method, which will always be tested and supported by the project.
Additionally, drop support for Debian 9 as it is now EOL.
This makes the installation a bit more secure by ensuring a user does not accidentally expose a way for unauthorized users to add new ssh keys to the system.
Additionally, this removes the extra HOSTNAME file to make the initial install process easier (that file was not modifiable by any dokku commands.
Closes#2247
As of April 2021, it will no longer be an LTS release, and thus us supporting it will increase maintenance burdens.
Also switch CI to use 18.04, so as to test what we currently support.
Closes#4505
While the latest packages may continue to work on other releases, we will no longer officially support these releases, nor will we distribute packages.
This script previously ran through the docker installation process with the edge channel on each run. Instead, we only run the docker installation if docker is not available. In addition, we force set the channel to stable, ensuring the script installs the correct channel for stable docker installations.
Closes#3269
While I do not agree with _every_ style change, this will force Dokku to have consistent formatting across all shell scripts, which is arguably a Good Thing™.
The command used to reprocess everything is:
```shell
shfmt -l -bn -ci -i 2 -w .
```
