Hi,

please take a look at my inline comments:

On Tue, Sep 27, 2016 at 7:23 PM, Gervais de Montbrun <gervais@demontbrun.com> wrote:

Hey All,

Since updating to 4.0.x of oVirt, I have had an issue with my hosted engine. After a some poking around, I think I have figured out my issue and thought I would share to see what others think.

The issue has existed with 4.0, 4.0.1, 4.0.2, 4.0.3, and still exists in 4.0.4.

Description:

When my hosted engine starts it reports that it is in a degraded state with 7 or 8 services still not started when I run systemctl status. It takes about 6 or 7 minutes to eventually start all the services and come online. If I don't set my cluster to Global-Maintenance mode it eventually thinks that my hosted-engine needs to be rebooted and restarts it before it can start everything.

​Could you please share with us logs gathered by ovirt-log-collector?

It's just a guess but could you please take a look if you HE VM has enough entropy?

  cat /proc/sys/kernel/random/entropy_avail

If the value is low (below or around 200),  you really need to install and configure some entropy generator such as haveged

Solution:

I realized that Apache was the culprit and found that the proxy to the ovirt-engine in /etc/httpd/conf.d/z-ovirt-engine-proxy.conf has a super long timeout with many retries. I changed the settings and now everything works for me.

-> Before change:

    <LocationMatch ^/(ovirt-engine($|/)|api($|/)|RHEVManagerWeb/|OvirtEngineWeb/|ca.crt$|engine.ssh.key.txt$|rhevm.ssh.key.txt$)>

        ProxyPassMatch ajp://127.0.0.1:8702 timeout=3600 retry=5

        <IfModule deflate_module>

            AddOutputFilterByType DEFLATE text/javascript text/css text/html text/xml text/json application/xml application/json application/x-yaml

        </IfModule>

    </LocationMatch>

-> After change:

    <LocationMatch ^/ovirt-engine($|/)>

        ProxyPassMatch ajp://127.0.0.1:8702 timeout=5 retry=2

        <IfModule deflate_module>

            AddOutputFilterByType DEFLATE text/javascript text/css text/html text/xml text/json application/xml application/json application/x-yaml

        </IfModule>

    </LocationMatch>

​This one is correct for 4.0​

​, not sure why it was not updated during upgrade from 3.6. @Simone?
​

 

If I read the timeout settings correctly, it will wait 60 minutes with 5 retries. 5 hours is way too long for my little server to hold onto all those apache processes.

The change I made allows for there to be an error, and also releases apache's hold on the process. Once everything is ready, apache is ready to serve requests and everything/everyone is happy. Before making the change, I just get a whitescreen in my browser and then nothing works until I restart Apache (or I end up in an endless loop of ovirt-ha services restarting my hosted-engine.

​Well, if you have an issue with too many apache processes waiting for engine to respond, then there's some issue in engine. As I wrote above please share the logs with us and check entropy.

Thanks

Martin Perina
​

 

I noticed that this setting reverts to the original setting, so oVirt must be writing this file. Perhaps these number can be changed in oVirt? If not, I will just setup and ansible play to revert the settings with working values and restart apache on my engine.

:-)

Cheers,
Gervais

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