Overlay: Add an [Install] section to flanneld.service

[danderson]

I have automation set up to configure flanneld on machine installation via Ignition. However, Ignition is unable to enable flanneld, because the systemd unit file provided in the coreos image doesn't have an [Install] section. Per the semantics of systemd units, this section cannot be provided in a drop-in unit, which leaves Ignition no way of setting flannel to start automatically on system boot.

Please consider adding an [Install] section to coreos-overlay/app-admin/flannel/files/flanneld.service that targets multi-user.target (like e.g. locksmithd does). Happy to provide a PR for this as well, if there's no objection.

[mischief]

systemctl add-wants and systemctl add-requires commands can accomplish a
similar goal regardless of the [Install] section of a unit. The [Install]
section usually just determines what symlinks will be created as part of
systemctl enable.
On Jan 30, 2016 1:10 AM, "Dave Anderson" notifications@github.com wrote:

I have automation set up to configure flanneld on machine installation via
Ignition However, Ignition is unable to enable flanneld, because the
systemd unit file provided in the coreos image doesn't have an [Install]
section Per the semantics of systemd units, this section cannot be provided
in a drop-in unit, which leaves Ignition no way of setting flannel to start
automatically on system boot

Please consider adding an [Install] section to
coreos-overlay/app-admin/flannel/files/flanneldservice that targets
multi-usertarget (like eg locksmithd does) Happy to provide a PR for this
as well, if there's no objection

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Reply to this email directly or view it on GitHub
#1102.

[danderson]

Unlike cloud-config, Ignition doesn't let you run arbitrary commands, so I can't make it run systemctl add-wants/add-requires without setting up a rube goldberg device of one-time units. The only operation it supports is enabling a systemd unit by making use of its [Install] section. Given the choice between adding an [Install] section to flannel, and adding a non-orthogonal config mechanism to Ignition to work around missing install sections, adding [Install] seems much cleaner.

[marineam]

Yup, this needs to happen. The missing install section is an artifact from cloudinit days where enabling etcd dependent services instead of starting them directly would generally cause problems.