First off, I'm a CentOS and Linux noob, so I'm pretty blind when working on the system.
I had installed and have been running Nagios 4.4.2 with NagiosQL 3.4.0 and all was well until a batch of CentOS updates I ran yesterday. Now when I open the NagiosQL page, I just get a blank screen in Firefox or an HTTP 500 error in Chrome. NAgios itself seems to be running fine, though. I saw a couple other similar posts here where it was suggested that we make sure pear is installed (I did that) and that Apache has permissions, which I also tried to ensure. For the hell of it, I tried to install NagiosQL 3.4.1 according to the instructions, ran that without issue and was then treated to the same blank page on the new version.
What are my next steps to troubleshoot? The apache logs just seemt o show the 500 error and browser that received it. Part of me wants to restore my backup from this weekend, but I'd like to fix the issue rather than revert to an out-of-date CentOS and then avoid updating.
Apologies for my lack of Linux troubleshooting knowledge.
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Most of these "blank page" problems with CentOS are based on the behavior of SELinux. Please check your SELinux logs and/or configuration to find out if SELinux blocks something.
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I took a look at the log, but didn't see anything that looked specific to this being blocked. Not knowing a whole lot about selinux (or linux in general), I disabled selinux as a test (selinux status is currently disabled). It looks like the blank pages still pop with it disabled. Is there anywhere else I can check for this sort of behavior?
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Another behavior could be, that php-pear is not installed. But after an upgrade such things should not be gone.
Are there some messages in Apache Error log? I have never used CentOS before - so I only know the problems with this OS from other users who reported them.
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Sorry for the double post, but I'm also able to see sub folders from a web browser. For example, my base path ('/var/www/html/nagiosql-3.4.1/') shows a blank page in the web browser, but if I manually head to one of the sub-folders (e.g. /config/), I'll see the directory and file index via the browser. It looks to be that way for other folders, as well (exceptions being the admin and base folders). Permissions look the same on each folder and files within, though.
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Sorry for the triple-post, but I think it definitely had to do with pear as you suggested in another thread. I ended up enabling error outputs in the browser and saw a failure for pear. I installed Pear and it now seems to be running with a timezone warning. Sorry for the trouble and than you for the help
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I waited a little while to give you time to check the PEAR installation. This is also one of the main reasons, because the HTML templates are loaded via a PEAR function.
The access_log usually says nothing - more interesting is the error_log. It shows access problems or missing functions - but unfortunately not always.
Then I can assume that NagiosQL now works as intended again?
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First off, I'm a CentOS and Linux noob, so I'm pretty blind when working on the system.
I had installed and have been running Nagios 4.4.2 with NagiosQL 3.4.0 and all was well until a batch of CentOS updates I ran yesterday. Now when I open the NagiosQL page, I just get a blank screen in Firefox or an HTTP 500 error in Chrome. NAgios itself seems to be running fine, though. I saw a couple other similar posts here where it was suggested that we make sure pear is installed (I did that) and that Apache has permissions, which I also tried to ensure. For the hell of it, I tried to install NagiosQL 3.4.1 according to the instructions, ran that without issue and was then treated to the same blank page on the new version.
What are my next steps to troubleshoot? The apache logs just seemt o show the 500 error and browser that received it. Part of me wants to restore my backup from this weekend, but I'd like to fix the issue rather than revert to an out-of-date CentOS and then avoid updating.
Apologies for my lack of Linux troubleshooting knowledge.
Most of these "blank page" problems with CentOS are based on the behavior of SELinux. Please check your SELinux logs and/or configuration to find out if SELinux blocks something.
I took a look at the log, but didn't see anything that looked specific to this being blocked. Not knowing a whole lot about selinux (or linux in general), I disabled selinux as a test (selinux status is currently disabled). It looks like the blank pages still pop with it disabled. Is there anywhere else I can check for this sort of behavior?
Another behavior could be, that php-pear is not installed. But after an upgrade such things should not be gone.
Are there some messages in Apache Error log? I have never used CentOS before - so I only know the problems with this OS from other users who reported them.
Are those the httpd access_logs? All I see there are the 500 errors:
Sorry for the double post, but I'm also able to see sub folders from a web browser. For example, my base path ('/var/www/html/nagiosql-3.4.1/') shows a blank page in the web browser, but if I manually head to one of the sub-folders (e.g. /config/), I'll see the directory and file index via the browser. It looks to be that way for other folders, as well (exceptions being the admin and base folders). Permissions look the same on each folder and files within, though.
Sorry for the triple-post, but I think it definitely had to do with pear as you suggested in another thread. I ended up enabling error outputs in the browser and saw a failure for pear. I installed Pear and it now seems to be running with a timezone warning. Sorry for the trouble and than you for the help
I waited a little while to give you time to check the PEAR installation. This is also one of the main reasons, because the HTML templates are loaded via a PEAR function.
The access_log usually says nothing - more interesting is the error_log. It shows access problems or missing functions - but unfortunately not always.
Then I can assume that NagiosQL now works as intended again?
Yeah, we're looking good. Thanks again for following up and thanks again for your help, Martin