This is more of a note to remind me how to fix it next time, but it could come
in handy for others in the same situation.
I restarted my virtual private server this morning, and after it came back up I
noticed none of the websites would load. The server runs
Varnish as a front end to all the websites,
and all it was doing was throwing up 503 errors and guru meditations. This means
that varnish can’t connect to any web server. The websites on the host are
served by nginx and apache. I double checked that they were running and that
they were on their correct ports with
tcp 0 0 0.0.0.0:8008 0.0.0.0:* LISTEN 391/apache2 tcp 0 0 0.0.0.0:88 0.0.0.0:* LISTEN 12365/nginx.conf
Ok, everything is running, why won’t it work!! Next is to try to telnet to the
telnet localhost 8008
That’s odd, it never connects. Let me try it from my computer (IP address
obscured. Why? I don’t know, it seems like a good idea :-).
telnet 220.127.116.11 8008
It connects right away. So for some reason, the server can’t connect to other
services on itself, even localhost. After some searching I came across a post
that mentions that sometimes the loopback interface doesn’t come up. I check:
[email protected]:~# ifconfig venet0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 inet addr:127.0.0.2 P-t-P:127.0.0.2 Bcast:0.0.0.0 Mask:255.255.255.255 UP BROADCAST POINTOPOINT RUNNING NOARP MTU:1500 Metric:1 RX packets:32802 errors:0 dropped:0 overruns:0 frame:0 TX packets:35269 errors:0 dropped:52 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:10716892 (10.7 MB) TX bytes:25360227 (25.3 MB) venet0:0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 inet addr:18.104.22.168 P-t-P:22.214.171.124 Bcast:0.0.0.0 Mask:255.255.255.255 UP BROADCAST POINTOPOINT RUNNING NOARP MTU:1500 Metric:1
I’ll be a monkey’s uncle, the loopback interface isn’t up! A quick
sudo and I am back in business!
ifconfig lo up