ajoergensen/baseimage-almalinux repository overview

⁠AlmaLinux baseimage

A baseimage based on AlmaLinux with Skarnet's s6 process supervision⁠ installed Just Container's s6 Overlay⁠ and several 3rd party repositories.

Bits and pieces have been sourced from other fine Docker images

These 3rd party repositories have been installed and enabled:

• EPEL (Extra Packages for Enterprise Linux)⁠
• MariaDB⁠ (to get latest MariaDB libs and client if needed)

Available tags: 8 and 9 (latest points to 9)

⁠Environment

• PUID - Changes the uid of the app user, default 911
• PGID - Changes the gid of the app group, default 911
• DISABLE_CRON - Do not run cron. Default is FALSE
• CRON_EMAIL - If set to false crond will log to syslog instead of sending emails. Default si FALSE
• DISABLE_SYSLOG - If set to TRUE, do not run rsyslog inside the container. Default is FALSE
• REMOTE_SYSLOG_HOST - If you want to log to a remote syslog server, set this variable to the IP or DNS name of the server. Remote logging is off by default.
• REMOTE_SYSLOG_PORT - Port used by the remote syslog server. Default is 514
• REMOTE_SYSLOG_PROTO - Protocol to use for the remote syslog server. Possible values are tcp or udp, default is tcp.
• SMTP_HOST - Change the SMTP relay server used by ssmtp (sendmail)
• SMTP_USER - Username for the SMTP relay server
• SMTP_PASS - Password for the SMTP relay server
• SMTP_PORT - Outgoing SMTP port, default 587
• SMTP_SECURE - Does the SMTP server requires a secure connection, default TRUE if SMTP_USER is set.
• SMTP_TLS - Use STARTTLS, default TRUE (if SMTP_TLS is FALSE and SMTP_SECURE is true, SMTP over SSL will be used)
• SMTP_MASQ - Masquerade outbound emails using this domain, default empty

⁠Running applications

It is recommended to run applications as the unpriviledged user app.

To run the application, add a start-up script like this

#/usr/bin/with-contenv bash
exec s6-setuidgid app /path/to/application

One shortcoming is the fact s6-setuigid does not set the $HOME variable. The work-around looks like this:

#/usr/bin/with-contenv bash
export HOME="~app"
exec s6-setuidgid app /path/to/application

⁠Email

If you need to send mail and cannot use SMTP directly, ssmtp is installed to provide /usr/bin/sendmail and is configured using the SMTP_ variables.

If SMTP_USER is not set, unauthenticated SMTP will be used and SSL/TLS is disabled.

⁠Persistent data

Generally I store configuration data in /config and store it in a volume. If an application does not permit changing the location of its configuration data, add a script to /etc/cont-init.d which changes the app user's $HOME