[ome-users] Nginx 502 Bad Gateway

[Harri Jäälinoja]

Hi all,

I managed to make OMERO web work with a separate Nginx instance 
listening at port 8000. So I think the problem must have started by 
running Nginx as root, with the configuration given by "omero web config 
nginx".

[omero at lmu-omero2 ~]$ omero web start
Starting OMERO.web... [OK]
[omero at lmu-omero2 ~]$ omero web status
OMERO.web status... [RUNNING] (PID 29142)
[omero at lmu-omero2 ~]$ /usr/sbin/nginx -c /home/omero/nginx8000.conf
[omero at lmu-omero2 ~]$

I would prefer to use the standard chkconfig system to start Nginx upon 
server reboot, so if you have ideas how to fine-tune the config to fit 
that scenario, please let me know.

Thanks, regards,
Harri


On 20/03/12 17:30, Harri Jäälinoja wrote:
> Hi Carlos,
>
> [root at lmu-omero2 nginx]# grep 4080 nginx.conf
> #fastcgi_pass 0.0.0.0:4080;
> fastcgi_pass 127.0.0.1:4080;
> [root at lmu-omero2 nginx]# netstat -ntlp|grep 80
> tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 28053/nginx
> tcp 0 0 0.0.0.0:4080 0.0.0.0:* LISTEN 31592/python
>
> I modified nginx.conf and restarted, but I still get the same error
> messages. But this is now run as root, where Chris said the config might
> need some other tweaking as well. If you know other things to modify,
> please let me know. In the mean time let's see if I manage to allow
> access to port 8000 to test a separate nginx instance...
>
> Regards,
> Harri
>
> On 20/03/12 17:06, C Neves wrote:
>> Hello Harri,
>>
>> Taking a closer look at this thread it seems that the nginx.conf you are
>> using has:
>>
>> fastcgi_pass 0.0.0.0:4080
>>
>> Which looks wrong to me. Listening on 0.0.0.0 is fine (all interfaces)
>> but this is where the nginx fastcgi handler will be connecting to. Can
>> you change that to 127.0.0.1 and retry?
>>
>> Regards,
>> Carlos
>>
>> On 2012/3/20 3:02 , Harri Jäälinoja wrote:
>>> Hi Chris,
>>>
>>>> How did you start nginx? As the omero user or as root?
>>>> If you are going to run nginx on port 80 it will need to be started
>>>> as root in order to bind to lower port numbers.
>>>>
>>> I started it as root, via "service nginx start".
>>>
>>>
>>>>> OMERO.web status... [NOT STARTED]
>>>>>
>>>>>
>>>>> So OMERO.web is not starting, even though there is no error:
>>>>>
>>>>> [omero at lmu-omero2 ~]$ omero web start
>>>>> Starting OMERO.web... Removed stale
>>>>> /opt/OMERO/OMERO.server-Beta-4.3.3/var/django.pid
>>>>> [OK]
>>>>
>>>> is anything listening to port 4080?
>>>>
>>>> # netstat -ntlp |grep 4080
>>>>
>>>
>>> Yes:
>>> [omero at lmu-omero2 ~]$ netstat -ntlp |grep 4080
>>> (Not all processes could be identified, non-owned process info
>>> will not be shown, you would have to be root to see it all.)
>>> tcp 0 0 0.0.0.0:4080 0.0.0.0:*
>>> LISTEN 31592/python
>>>
>>>
>>>
>>>>
>>>> I'm assuming nothing of interest in $OMERO_HOME/var/log/OMEROweb*?
>>>>
>>>
>>> No, just "Application Starting...".
>>>
>>>> Are you running under selinux by chance?
>>>>
>>>> # sestatus
>>>>
>>>
>>> No.
>>> [root at lmu-omero2 nginx]# sestatus
>>> SELinux status: disabled
>>>
>>>
>>>>>>
>>>>>> [omero at lmu-omero2 ~]$ omero web config nginx
>>>>
>>>> This generated config is more designed around running a separate
>>>> nginx instance as a non-priviledged user on a different port.
>>>>
>>>> That config would need to be tweaked a little to run as a root
>>>> instance.
>>>>
>>>
>>> Ok. I noticed now also the example in "omero web -h", that looks like
>>> a separate instance.
>>>
>>>> As far as avoiding compiling fastcgi, if you add the rpmforge
>>>> repositories
>>>> (http://wiki.centos.org/AdditionalResources/Repositories/RPMForge
>>>> those are centos instructions but are true for RHEL as well) it has
>>>> fastcgi packages.
>>>>
>>>
>>> Ok, I can try this as well, see which one the other admins like better.
>>>
>>>
>>>> But nginx's configuration is secondary to why omero web doesn't seem
>>>> to be starting correctly.
>>>>
>>>
>>> But the process that is listening at port 4080 should be omero web,
>>> right? What does "omero web status" check, maybe it's just the check
>>> that is going wrong?
>>>
>>> Thanks,
>>> Harri
>>>
>>
>> _______________________________________________
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>> ome-users at lists.openmicroscopy.org.uk
>> http://lists.openmicroscopy.org.uk/mailman/listinfo/ome-users
>
>


-- 
__________________________________________________
Harri Jäälinoja
Light Microscopy Unit
Institute of Biotechnology, University of Helsinki
http://www.biocenter.helsinki.fi/bi/lmu/
+358 9 191 59370 fax +358 9 191 59366