How to change the log level of Cloudflare's warp-svc on Linux

If you’re using Cloudflare’s WARP on Linux, you’ll probably notice that the warp-svc service pollutes syslog quite a lot:

$ journalctl -b -u warp-svc
...
Oct 20 21:15:01 mypc warp-svc[900]: 2024-10-20T14:15:01.026Z  INFO warp::warp_service::ipc_loop: IPC...
Oct 20 21:15:02 mypc warp-svc[900]: 2024-10-20T14:15:02.381Z DEBUG main_loop: warp::warp_service::ipc_handlers: Ipc...
...

Lots of info and debug messages here. By default, this service’s log level is debug. No wonder!

It looks like Cloudflare provides no configuration option for changing its log level. Luckily, we can change it by setting LogLevelMax option in warp-svc’s SystemD unit file (see docs here).

• First, let’s find out the path to unit file:

$ systemctl cat warp-svc.service
# /lib/systemd/system/warp-svc.service
...

• Next, open the unit file and add LogLevelMax=err to the [Service] section. This change the log level to error instead of debug. The resulting file should look something like this:

$ cat /lib/systemd/system/warp-svc.service
[Unit]
Description=Cloudflare Zero Trust Client Daemon
After=pre-network.target

[Service]
Type=simple
ExecStart=/bin/warp-svc
DynamicUser=no
CapabilityBoundingSet=CAP_NET_ADMIN CAP_NET_BIND_SERVICE CAP_SYS_PTRACE
AmbientCapabilities=CAP_NET_ADMIN CAP_NET_BIND_SERVICE CAP_SYS_PTRACE
StateDirectory=cloudflare-warp
RuntimeDirectory=cloudflare-warp
LogsDirectory=cloudflare-warp
Restart=always
LogLevelMax=err    # Set the log level here

[Install]
WantedBy=multi-user.target

• Reload the unit file and restart warp-svc:

$ sudo systemctl daemon-reload
$ sudo systemctl restart warp-svc.service

• Finally, check the syslog. warp-svc should no longer spam syslog with info and debug messages anymore.

P.S. Another way to modify the SystemD unit file is to use this command:

$ sudo systemctl edit warp-svc.service