Autopause not working in java8 tag

[Caedis]

Getting an error on startup:

sudo: unable to execute /usr/local/sbin/knockd: No such file or directory
[Autopause loop] Failed to start knockd daemon.
[Autopause loop] Probable cause: Unable to attach to interface "eth0".
[Autopause loop] Available interfaces within the docker container:
[Autopause loop]   eth0
[Autopause loop] Please set the environment variable AUTOPAUSE_KNOCK_INTERFACE to the interface that handles incoming connections.
[Autopause loop] If unsure which interface to choose, run the ifconfig command in the container.
[Autopause loop] Autopause failed to initialize. This log entry will be printed every 30 minutes.

Guessing one of the issues is:

docker-minecraft-server/files/autopause/autopause-daemon.sh

Line 42 in 48414b3

sudo /usr/sbin/knockd -c /tmp/knockd-config.cfg -d -i "$AUTOPAUSE_KNOCK_INTERFACE"

Going into the container gives:

bash-4.4# which knockd
/usr/local/sbin/knockd
bash-4.4# which knock
/usr/local/bin/knock

[itzg]

@Metalcape it looks like Alpine support is broken for auto-pause. I'm guessing it's because Alpine uses musl instead of glibc and the binary needs to be built accordingly. Statically linking would probably solve it too. Can you research this some?

[Metalcape]

I've looked into it and apparently static linking isn't possible due to certain functions like getaddrinfo that still require the glibc binary even when statically linked. For alpine we only support amd64 right? Dealing with musl cross-compilers seems complicated.

[itzg]

Correct, Alpine is only amd64.

I'm also thinking we can use the unpatched knockd on Alpine and symlink things into the same location.

[itzg]

...in fact, I'm now thinking that either way the knockd installation at

docker-minecraft-server/Dockerfile

Lines 55 to 58 in f649389

	# Install modified knockd
	ADD https://github.com/Metalcape/knock/releases/download/0.8.1/knock-0.8.1-${TARGETARCH}${TARGETVARIANT}.tar.gz /tmp/knock.tar.gz
	RUN tar -xf /tmp/knock.tar.gz -C /usr/local/ && rm /tmp/knock.tar.gz
	RUN find /usr/lib -name 'libpcap.so.0.8' -execdir cp '{}' libpcap.so.1 \;

should probably be situated in the build/*/install-packages.sh scripts. In which, case altering the alpine installation is quite natural to alter via that mechanism.