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kenn's questions

Martin Hope
kenn
Asked: 2013-01-11 23:36:38 +0800 CST
  • 5

And what are performance implications? Is it practical to host tens of thousands of vhosts on one Nginx instance? How much would the increased latency be?

We plan to offer custom domains for users, and to assign different chroot per user and to serve static assets like js/css directly from nginx, we want to host as many users per nginx instance as possible.

nginx
Martin Hope
kenn
Asked: 2012-09-06 09:41:41 +0800 CST
  • 1

We have multiple projects to be monitored with Munin, and naturally we have a separate Munin server for each project.

But now that we're using Munin 2.0 + Nginx/fcgi and it's scalable with many munin-nodes, I'm thinking if it's possible to co-host all projects with a single Munin server.

Requirements are:

  • Access control: an owner of a project can't view another project's munin graphs
  • Maintainability: Single binary update on the server

Is it possible?

nginx
Martin Hope
kenn
Asked: 2012-02-23 22:31:21 +0800 CST
  • 41

Usually, I run aptitude -y install locales then dpkg-reconfigure locales to set up locale.

Now I want to put it into a shell script, how can I reliably do the following, automatically / non-interactively?

  • Choose en_US.UTF-8 and set it as system default
  • Disable all other locales
  • (Optional) Verify if /etc/default/locale contains one-and-only entry of LANG=en_US.UTF-8 as expected
ubuntu debian localization shell-scripting
Martin Hope
kenn
Asked: 2011-05-03 09:36:27 +0800 CST
  • 3

We occasionally have seen time differences on our servers, and confirmed that:

  • ntpd crashed without any traceable logs
  • ntpq process was dead, but pid existed at /var/run/ntpd.pid
  • /etc/init.d/ntp restart then ntpq -p, problem solved

At first, ntpq -p returned ntpq: read: Connection refused, so I went ahead and ps aux | grep ntp returned no ntp process, while other working hosts returned something like /usr/sbin/ntpd -p /var/run/ntpd.pid -u 101:103 -g. It seemed that ntpd actually crashed since no logs seen in /var/log/messages, but it's possible that it happened too long ago and that part in the log was already rotated.

So I went on to /etc/init.d/ntp restart and was told that the stale pid existed:

Stopping NTP server: ntpdstart-stop-daemon: warning: failed to kill 2124: No such process`.
Starting NTP server: ntpd.

but everything got back in place.

We're on Debian 6 Squeeze but the problem has been around since Debian 5 Lenny. We installed ntp using aptitude install ntp. Servers are on Linode VPS (= Xen virtualization), so we asked them but they said they had no experience like this.

Also, though I don't know if it's just a coincidence or not, it seems that it happens only on application servers (Ruby on Rails) so far.

Thing is, since the pid file remains when ntpd crashes, it's pretty hard to detect the crash and restart with monit or alike. Should I call /etc/init.d/ntp restart every once in a while by cron?

Any experiences, solutions, thoughts?

debian ntp