Fedora Unix socket file location problems

Eric Wong
2013-04-05T21:56:09Z

David Wilkins <dwilkins at conecuh.com> wrote:
> Folks,
>
> It seems that it''s pretty common to use /tmp for the directory
where
> you store the Unicorn unix: socket file.   I''m a Fedora user and
our
> lovable systemd (by default) gives nginx a private /tmp directory (see
> "PrivateTmp=true" in system configuration file example below).
> That''s the kind of thing that *could* take a while to figure out.
>
> Could you put a note somewhere near the listen docs warning Fedora /
> systemd users to locate the socket file somewhere else?  I know
it''s
> not your problem, but I''ll bet that more than a few Fedora users
are
> using TCP sockets instead of unix sockets with Unicorn because of
> this.

Thanks, I''ll queue up something like the following patch.
Comments/corrections greatly appreciated:

------------------------------8<-------------------------------
From: Eric Wong <normalperson at yhbt.net>
Subject: [PATCH] doc: update documentation for systemd + PrivateTmp users

The PrivateTmp feature of systemd breaks the usage of /tmp for the
shared Unix domain socket between nginx and unicorn, so discourage the
use of /tmp in that case.

While we''re at it, use consistent paths for everything and use an
obviously intended-for-user-customization "/path/to" prefix instead
of "/tmp"

ML-Ref: CAKLVLx_t+9zWMhquMWDfStrxS7xrNoGmN0ZDsjSCUE=VxU+oyQ at mail.gmail.com
Reported-by: David Wilkins <dwilkins at conecuh.com>
---
 examples/nginx.conf         |  8 ++++----
 examples/unicorn.conf.rb    |  2 +-
 lib/unicorn/configurator.rb | 10 ++++++++--
 3 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/examples/nginx.conf b/examples/nginx.conf
index 66ac0aa..a68fe6f 100644
--- a/examples/nginx.conf
+++ b/examples/nginx.conf
@@ -24,8 +24,8 @@ user nobody nogroup; # for systems with a "nogroup"
 # user nobody nobody; # for systems with "nobody" as a group instead

 # Feel free to change all paths to suite your needs here, of course
-pid /tmp/nginx.pid;
-error_log /tmp/nginx.error.log;
+pid /path/to/nginx.pid;
+error_log /path/to/nginx.error.log;

 events {
   worker_connections 1024; # increase if you have lots of clients
@@ -42,7 +42,7 @@ http {
   default_type application/octet-stream;

   # click tracking!
-  access_log /tmp/nginx.access.log combined;
+  access_log /path/to/nginx.access.log combined;

   # you generally want to serve static files with nginx since neither
   # Unicorn nor Rainbows! is optimized for it at the moment
@@ -74,7 +74,7 @@ http {
     # single worker for timing out).

     # for UNIX domain socket setups:
-    server unix:/tmp/.sock fail_timeout=0;
+    server unix:/path/to/.unicorn.sock fail_timeout=0;

     # for TCP setups, point these to your backend servers
     # server 192.168.0.7:8080 fail_timeout=0;
diff --git a/examples/unicorn.conf.rb b/examples/unicorn.conf.rb
index 4042d9c..9dce58a 100644
--- a/examples/unicorn.conf.rb
+++ b/examples/unicorn.conf.rb
@@ -25,7 +25,7 @@

 # listen on both a Unix domain socket and a TCP port,
 # we use a shorter backlog for quicker failover when busy
-listen "/tmp/.sock", :backlog => 64
+listen "/path/to/.unicorn.sock", :backlog => 64
 listen 8080, :tcp_nopush => true

 # nuke workers after 30 seconds instead of 60 seconds (the default)
diff --git a/lib/unicorn/configurator.rb b/lib/unicorn/configurator.rb
index 7651093..0d0eac7 100644
--- a/lib/unicorn/configurator.rb
+++ b/lib/unicorn/configurator.rb
@@ -188,7 +188,7 @@ def before_exec(*args, &block)
   #    # on nginx upstream configuration:
   #    upstream unicorn_backend {
   #      # for UNIX domain socket setups:
-  #      server unix:/path/to/unicorn.sock fail_timeout=0;
+  #      server unix:/path/to/.unicorn.sock fail_timeout=0;
   #
   #      # for TCP setups
   #      server 192.168.0.7:8080 fail_timeout=0;
@@ -229,9 +229,15 @@ def listeners(addresses) # :nodoc:
   #
   #   listen 3000 # listen to port 3000 on all TCP interfaces
   #   listen "127.0.0.1:3000"  # listen to port 3000 on the loopback
interface
-  #   listen "/tmp/.unicorn.sock" # listen on the given Unix domain
socket
+  #   listen "/path/to/.unicorn.sock" # listen on the given Unix
domain socket
   #   listen "[::1]:3000" # listen to port 3000 on the IPv6 loopback
interface
   #
+  # When using Unix domain sockets, be sure:
+  # 1) the path matches the one used by nginx
+  # 2) uses the same filesystem namespace as the nginx process
+  # For systemd users using PrivateTmp=true (for either nginx or unicorn),
+  # this means Unix domain sockets must not be placed in /tmp
+  #
   # The following options may be specified (but are generally not needed):
   #
   # [:backlog => number of clients]
--
Eric Wong