- Plesk Onyx for Linux
Unable to access Plesk: 502 Bad Gateway error is shown.
the following error is shown:
2017/02/25 11:21:58 [error] 29398#0: *11 recv() failed (104: Connection reset by peer) while reading response header from upstream, client: xxx.xxx.xxx.xxx, server: , request: "POST /login_up.php3 HTTP/1.1", upstream: "fastcgi://unix:/var/run/sw-engine.sock:", host: "xxx.xxx.xxx.xxx:8443", referrer: "https://xxx.xxx.xxx.xxx:8443/login_up.php3"
/var/log/syslog or in /var/log/messages
the following message can be found:
Feb 25 12:55:21 server kernel: grsec: From xxx.xxx.xxx.xxx: process /usr/bin/sw-engine(sw-engine:3782) attached to via ptrace by /usr/bin/sw-engine[sw-engine:3785] uid/euid:0/0 gid/egid:0/0, parent /usr/bin/sw-engine[sw-engine:3782] uid/euid:0/0 gid/egid:0/0
Feb 25 12:55:22 server kernel: grsec: From xxx.xxx.xxx.xxx: denied ptrace of /usr/bin/sw-engine(sw-engine:3793) by /usr/bin/sw-engine[sw-engine:3796] uid/euid:999/0 gid/egid:1000/1000, parent /usr/bin/sw-engine[sw-engine:3793] uid/euid:999/0 gid/egid:1000/1000
Unable to install any application, it hangs on 0% or 1%.
Unable to update plugins.
OS uses grsec kernel which is not supported by Plesk with enabled ptrace which does not allow Plesk work normally.
Disable ptrace by adding the following line into
kernel.grsecurity.harden_ptrace = 0
Reload system variables:
# sysctl -p
If the issue persists after above steps, reboot the system using standart CentOS kernel.
Contact Grsec support team.