matrix-docker-ansible-deploy/roles/matrix-mailer/templates/systemd/matrix-mailer.service.j2

[Unit]
Description=Matrix mailer
After=docker.service
Requires=docker.service

[Service]
Type=simple
ExecStartPre=-/usr/bin/docker kill matrix-mailer
ExecStartPre=-/usr/bin/docker rm matrix-mailer
ExecStart=/usr/bin/docker run --rm --name matrix-mailer \
			--log-driver=none \
			--user={{ matrix_mailer_container_user_uid }}:{{ matrix_mailer_container_user_gid }} \
			--cap-drop=ALL \
			--read-only \
			--tmpfs=/var/spool/exim:rw,noexec,nosuid,size=100m \
			--network={{ matrix_docker_network }} \
			--env-file={{ matrix_mailer_base_path }}/env-mailer \
			--hostname={{ matrix_server_fqn_matrix }} \
			{{ matrix_mailer_docker_image }}
ExecStop=-/usr/bin/docker kill matrix-mailer
ExecStop=-/usr/bin/docker rm matrix-mailer
Restart=always
RestartSec=30

[Install]
WantedBy=multi-user.target
Add email-sending support 6 years ago			`[Unit]`
			`Description=Matrix mailer`
			`After=docker.service`
			`Requires=docker.service`

			`[Service]`
			`Type=simple`
			`ExecStartPre=-/usr/bin/docker kill matrix-mailer`
			`ExecStartPre=-/usr/bin/docker rm matrix-mailer`
			`ExecStart=/usr/bin/docker run --rm --name matrix-mailer \`
Disable Docker container logging `--log-driver=none` is used for all Docker containers now. All these containers are started through systemd anyway and get logged in journald, so there's no need for Docker to be logging the same thing using the default `json-file` driver. Doing that was growing `/var/lib/docker/containers/..` infinitely until service/container restart. As a result of this, things like `docker logs matrix-synapse` won't work anymore. `journalctl -u matrix-synapse` is how one can see the logs. 6 years ago			`--log-driver=none \`
Make (most) containers start as non-root This makes all containers (except mautrix-telegram and mautrix-whatsapp), start as a non-root user. We do this, because we don't trust some of the images. In any case, we'd rather not trust ALL images and avoid giving `root` access at all. We can't be sure they would drop privileges or what they might do before they do it. Because Postfix doesn't support running as non-root, it had to be replaced by an Exim mail server. The matrix-nginx-proxy nginx container image is patched up (by replacing its main configuration) so that it can work as non-root. It seems like there's no other good image that we can use and that is up-to-date (https://hub.docker.com/r/nginxinc/nginx-unprivileged is outdated). Likewise for riot-web (https://hub.docker.com/r/bubuntux/riot-web/), we patch it up ourselves when starting (replacing the main nginx configuration). Ideally, it would be fixed upstream so we can simplify. 6 years ago			`--user={{ matrix_mailer_container_user_uid }}:{{ matrix_mailer_container_user_gid }} \`
Drop capabilities in containers We run containers as a non-root user (no effective capabilities). Still, if a setuid binary is available in a container image, it could potentially be used to give the user the default capabilities that the container was started with. For Docker, the default set currently is: - "CAP_CHOWN" - "CAP_DAC_OVERRIDE" - "CAP_FSETID" - "CAP_FOWNER" - "CAP_MKNOD" - "CAP_NET_RAW" - "CAP_SETGID" - "CAP_SETUID" - "CAP_SETFCAP" - "CAP_SETPCAP" - "CAP_NET_BIND_SERVICE" - "CAP_SYS_CHROOT" - "CAP_KILL" - "CAP_AUDIT_WRITE" We'd rather prevent such a potential escalation by dropping ALL capabilities. The problem is nicely explained here: https://github.com/projectatomic/atomic-site/issues/203 6 years ago			`--cap-drop=ALL \`
Make (most) containers run with a read-only filesystem 6 years ago			`--read-only \`
			`--tmpfs=/var/spool/exim:rw,noexec,nosuid,size=100m \`
Add email-sending support 6 years ago			`--network={{ matrix_docker_network }} \`
Split playbook into multiple roles As suggested in #63 (Github issue), splitting the playbook's logic into multiple roles will be beneficial for maintainability. This patch realizes this split. Still, some components affect others, so the roles are not really independent of one another. For example: - disabling mxisd (`matrix_mxisd_enabled: false`), causes Synapse and riot-web to reconfigure themselves with other (public) Identity servers. - enabling matrix-corporal (`matrix_corporal_enabled: true`) affects how reverse-proxying (by `matrix-nginx-proxy`) is done, in order to put matrix-corporal's gateway server in front of Synapse We may be able to move away from such dependencies in the future, at the expense of a more complicated manual configuration, but it's probably not worth sacrificing the convenience we have now. As part of this work, the way we do "start components" has been redone now to use a loop, as suggested in #65 (Github issue). This should make restarting faster and more reliable. 6 years ago			`--env-file={{ matrix_mailer_base_path }}/env-mailer \`
Rename some variables 6 years ago			`--hostname={{ matrix_server_fqn_matrix }} \`
Rename playbook variables so they are consistently prefixed Pretty much all variables live in their own `matrix_<whatever>` prefix now and are grouped closer together in the default variables file (`roles/matrix-server/defaults/main.yml`). 6 years ago			`{{ matrix_mailer_docker_image }}`
Add email-sending support 6 years ago			`ExecStop=-/usr/bin/docker kill matrix-mailer`
			`ExecStop=-/usr/bin/docker rm matrix-mailer`
			`Restart=always`
			`RestartSec=30`

			`[Install]`
			`WantedBy=multi-user.target`