@0lmi I am absolutely speechless. I think that is absolutely the problem and thank you so much for your help.
The docker command does return 132:
karl@mender-test:~/integration-2.2.1$ sudo docker run -it -p 8888:80 openresty/openresty:1.13.6.2-0-alpine
karl@mender-test:~/integration-2.2.1$ echo $?
132
And dmesg snip shows the same opcode error:
[ 688.851186] traps: openresty[3560] trap invalid opcode ip:7f986ae17448 sp:7ffe09c479b0 error:0 in libluajit-5.1.so.2.1.0[7f986ae0f000+277000]
[ 689.326609] docker0: port 1(veth7b49596) entered disabled state
[ 689.328498] vethd100f45: renamed from eth0
[ 689.397711] docker0: port 1(veth7b49596) entered disabled state
[ 689.402546] device veth7b49596 left promiscuous mode
[ 689.402551] docker0: port 1(veth7b49596) entered disabled state
Seriously though, great catch, never would have expected that.