My two cents, since I've been using systemd for a while with solr.
Please keep in mind: these are my opinions, not something I'd be angry
about :D
On 4/15/20 10:30 PM, Marius Ghita wrote:
> [Unit]
> Description=Apache SOLR
>
> [Service]
> Type=forking
> User=solr
> Environment=SOLR_INCLUDE=/etc/default/solr.in.sh <http://solr.in.sh>
> ExecStart=/opt/solr/bin/solr start
> ExecStop=/opt/solr/bin/solr stop
> Restart=on-failure
> LimitNOFILE=65000
> LimitNPROC=65000
> TimeoutSec=180s
Here's my distribution's [Service] section for comparison:
[Service]
Type=simple
User=solr
Group=solr
PrivateTmp=true
WorkingDirectory=/opt/solr
ExecStart=/opt/solr/bin/solr start -f
To point out the differences:
- I'm starting solr as foreground service, so I don't even need to spec
ExecStop, and can use Type=simple instead of forking.
- PrivateTmp to ensure no secrets are world-readable
- Restart=always because I can't tell if failure in solr will always
cause an non-zero exit code, so I'd rather be safe than sorry. But that
could go in an override as well.
My [Service] overrides:
[Service]
LimitNOFILE=65000
LimitNPROC=65000
EnvironmentFile=/etc/conf.d/solr.env
and the contents of '/etc/conf.d/solr.env':
SOLR_HEAP="14g"
SOLR_DATA_HOME="/storage/solr"
ZK_HOST="solr0,solr1,solr2"
SOLR_HOST=solr0
> We don't need all those Before/After/Conflicts, users can customize
further the service via systemd drop-ins
I disagree. If you're using systemd everywhere, systemd will also do
networking. I don't know what would happen if your network is not
set-up, but I'd guess Solr will quit when there's not even a loopback to
connect to. I'm in favor for adding "After=network.target" to the [Unit]
section.
For the LimitN* you set as default, I'd say that they should go into
overrides, not into the default.
On the other hand, distributions that package Solr will change the unit
file anyways, so I'm not sure how much time we should spend on arguing
here :D
Another thing that might be interesting is socket activation.
For those unfamiliar: systemd listens on the port you want to start Solr
on. Once a connection comes in, systemd will start the unit and pass the
connection on.
There's only a few applications that support this (notably nginx) and
I'm not sure if lazily starting Solr is a valid use case.
I use it, but only for development: I have a Solr container installed
and systemd listening on [::]:8983. And if I want to use solr I just
connect to port 8983 and systemd will run the container and pass the
connection on.
Same could work for starting the solr service, but I think that would
need some work, so the connection hand-off will work.
best regards,
-1
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