From 75c4223a7f5a8a073ba0d898ef9d841fdaef2f63 Mon Sep 17 00:00:00 2001 From: Laurent Bercot Date: Wed, 21 Mar 2018 18:00:10 +0000 Subject: Add s6-svdt-clear, s6-permafailon --- doc/s6-permafailon.html | 98 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 98 insertions(+) create mode 100644 doc/s6-permafailon.html (limited to 'doc/s6-permafailon.html') diff --git a/doc/s6-permafailon.html b/doc/s6-permafailon.html new file mode 100644 index 0000000..f749d5f --- /dev/null +++ b/doc/s6-permafailon.html @@ -0,0 +1,98 @@ + + + + + + s6: the s6-permafailon program + + + + + + +

+s6
+Software
+skarnet.org +

+ +

The `s6-permafailon` program

+ +

+s6-permafailon is a program that is meant to be used +in the ./finish script of a +service directory supervised by +s6-supervise. When used, it +reads and analyses the death tally of a service (i.e. the recent +process death events that happened), and if the death tally +matches a given pattern, it causes permanent failure +of the service, i.e. it tells the supervisor not to try and +restart it. +

+ +

Interface

+ +

+     s6-permafailon secs deathcount events prog...
+

+ +

s6-permafailon must have the service directory of the +tested service as its current directory. This is the default if it is +called from the finish script of the service.
It reads the death tally of the service, which is +maintained by s6-supervise.
If the supervised process has died at least deathcount +times in the last secs seconds with a cause listed in +events, then s6-permafailon exits 125.
Else s6-permafailon execs into prog....

+ +

+ events is a comma-separated list of events. An event can be +one of the following: +

+ +

An exit code, which is an integer between 0 and 255. Example: 1
An exit code interval, which is two exit codes separated by a dash. Example: 1-50
A signal name, or a signal number preceded by "SIG". Examples: SIGTERM, sigabrt, sig11

+ +

Usage

+ +

s6-supervise detects when the ./finish +script of its service exits 125, and stops respawning the service. So, if the +./finish script is a chain-loading command line starting with a +s6-permafailon invocation (or containing such an invocation), when +s6-permafailon exits 125, then the ./finish script also +exits 125 (because it is the same process), and the service is then marked as +failing permanently.
The ./finish script is naturally a chain-loading +command line if it is written in the +execline language. It +can also be made into a chain-loading command line from a shell script by using +exec s6-permafailon secs deathcount events rest-of-chainloading-cmdline...
Multiple invocations of s6-permafailon can be chained, in order +to test several death patterns.
If a permanent failure is triggered and secs is high, it is +possible that when the administrator manually launches the service again, +the next death triggers a permanent failure again. If this is not wanted, +the administrator should clear the death tally with the +s6-svdt-clear command.
The current death tally can be viewed via the s6-svdt +command.

+ +

Example

+ +

+ s6-permafailon 60 5 1,101-103,SIGSEGV,SIBBUS prog... +will exit 125 if the service has died 5 times in the last 60 seconds with +an exit code of 1, 101, 102 or 103, a SIGSEGV or a SIGBUS. Else it will +chainload into the prog... command line. +

+ + + -- cgit v1.2.3

The s6-permafailon program

Interface

Usage

Example

The `s6-permafailon` program