systemd services does not support env variables in all blocks

[bchanan03]

Hi All,

I have a problem where i want to control where systemd service (fleet service) is running on multiple hosts cluster.

Problem:
MachineMetadata in X-Fleet block does not support environment variable exported in EnvironmentFile under Service block

Example: docker secure registry .service file

[Unit]
Description=secure registry service
After=docker.service
Requires=docker.service

[Service]
TimeoutStartSec=0
EnvironmentFile=/home/core/trust_authority/bin/env.sh
ExecStartPre=-/usr/bin/docker kill secure-registry
ExecStartPre=-/usr/bin/docker rm secure-registry
ExecStart=/usr/bin/docker run --rm -p 5000:5000 -v ${TA_DATA_PATH}/secure-registry/:/var/lib/registry -v ${TA_CONTAINER_PATH}/secure-registry/config.yml:/go/src/github.com/docker/distribution/cmd/registry/config.yml -v ${TA_CONTAINER_PATH}/secure-registry/certs.d/secure-registry:/certs -e REGISTRY_HTTP_TLS_CERTIFICATE=/certs/server.crt -e REGISTRY_HTTP_TLS_KEY=/certs/server.key -e SEARCH_BACKEND=sqlalchemy -e SQLALCHEMY_INDEX_DATABASE=sqlite:////tmp/docker-registry.db --name secure-registry secure-registry-${TA_DOMAIN}:5000/secure-registry
ExecStop=/usr/bin/bash -c "
/usr/bin/docker stop secure-registry;
"

[X-Fleet]
MachineMetadata=hostname=host01-il-${TA_DOMAIN}
Conflicts=secure-registry@*.service

[poettering]

Environment expansion is only supported in Exec= lines, and that's documented. the env vars are determined only at execution time, hence this is unlikely to be changed. Also, we really don#t want to turn unit files into a template language, hence we are unlikely to extend any evaluation logic much further anyway...

if you want a template language, consider using one, like shell or so, but unit files are not it, and that's documented.

[bchanan03]

in systemd perspective I understand the time when service is deployed and service is running
in fleet perspective it should allow making systemd services as template allow matching services on configurable hosts.

Example: I have 3 different lab all running same .services but each has its own top level domain
host01-il-private.saas.lab
host01-il-devops.saas.lab
host01-il-qa.saas.lab

Q: how can i create a service that will support each lab - same time keeping it simple
For that I wanted to create env.sh with TLD=private.saas.lab or devops.saas.lab or qa.saas.lab

[poettering]

This is a systemd bug tracker, not a fleet support forum. Please contact the fleet folks for help. thanks.