Plesk Panel won't load after Apache upgrade: ERROR: Service_Agent_Exception

[Gymnae]

PRODUCT, VERSION, MICROUPDATE, OPERATING SYSTEM, ARCHITECTURE
Plesk 11.5 - newest micropudate, Ubuntu 12.04 LTS, AMD64

PROBLEM DESCRIPTION
To upgrade the system wide PHP install and keep it updated I added an up-to-date repo to my sources. Before that I followed the PLESK admin manual to manually compile PHP and add that as an alternative also to the web interface, but after heartbleed it occured to me that updating PHP this way would mean recompiling for everytime, so I wanted to switch to a packaged and maintained version.

I followed a tutorial to upgrade Ubuntu 12.04 LTS with PHP 5.5:

sudo add-apt-repository ppa:ondrej/php5

followed by

sudo apt-get update && sudo apt-get dist-upgrade

This, apparently, also updated Apache to version 2.4

Now the Webserver still runs and feels much faster, but I cannot access the Plesk Panel anymore.
Navigating to the Login page results in the following error code:

Unable to read apache features from the service node: [Fri May 02 15:40:30.449387 2014] [core:warn] [pid 12377] AH00111: Config variable ${APACHE_LOCK_DIR} is not defined
[Fri May 02 15:40:30.449531 2014] [core:warn] [pid 12377] AH00111: Config variable ${APACHE_PID_FILE} is not defined
[Fri May 02 15:40:30.449645 2014] [core:warn] [pid 12377] AH00111: Config variable ${APACHE_RUN_USER} is not defined
[Fri May 02 15:40:30.449699 2014] [core:warn] [pid 12377] AH00111: Config variable ${APACHE_RUN_GROUP} is not defined
[Fri May 02 15:40:30.449767 2014] [core:warn] [pid 12377] AH00111: Config variable ${APACHE_LOG_DIR} is not defined
[Fri May 02 15:40:30.460356 2014] [core:warn] [pid 12377] AH00111: Config variable ${APACHE_LOCK_DIR} is not defined
[Fri May 02 15:40:30.461350 2014] [core:warn] [pid 12377] AH00111: Config variable ${APACHE_RUN_DIR} is not defined
[Fri May 02 15:40:30.466903 2014] [core:warn] [pid 12377] AH00111: Config variable ${APACHE_LOG_DIR} is not defined
[Fri May 02 15:40:30.466976 2014] [core:warn] [pid 12377] AH00111: Config variable ${APACHE_LOG_DIR} is not defined
AH00526: Syntax error on line 55 of /etc/apache2/apache2.conf:
Invalid Mutex directory in argument file:${APACHE_LOCK_DIR}
get_apache_path: '/usr/sbin/apache2 -V' failed

It could be that the PLESK Apache config is not picking up the envvars or is still expecting Apache 2.2

Right now I can do my admin through bash, but as Plesk overrides edits made to confi files of the webserver once it is running again, I'd like to make sure that I can access the web-interface again.

Cheers and a good weekend to all.

 

[Nikolay.]

Plesk 11.5 doesn't really support Apache 2.4, so your best bet is downgrading back to Apache 2.2.

 

[Gymnae]

Plesk 11.5 doesn't really support Apache 2.4, so your best bet is downgrading back to Apache 2.2.

Yeah, that was my idea now too. but how can I do that without

apt-get apache2

Because if I try this, I get:

root@xxx:~# apt-get remove apache2=2.4.9-1+deb.sury.org~precise+1
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages will be REMOVED:
  apache2 apache2-mpm-prefork libapache2-mod-aclr2-psa libapache2-mod-fcgid-psa libapache2-mod-php5 libapache2-mod-rpaf-psa
  libapache2-mod-sysenv-psa plesk-core plesk-l10n plesk-management-node plesk-web-hosting pp-sitebuilder psa-firewall psa-horde
  psa-imp psa-ingo psa-kronolith psa-migration-agents psa-migration-manager psa-mnemo psa-passwd psa-php5-configurator psa-phpmyadmin
  psa-phppgadmin psa-turba psa-updates

But I only want to switch another version of apache2

 

[Nikolay.]

apt-get install apache2=2.2

or something like that (you might need to specify the exact version).

 

[Tozz]

Also, Plesk does not support dist-upgrading a Debian-like system (such as Ubuntu) as of this moment. You have to perform a server to server mgration using Plesk's migration manager.

 

[Gymnae]

Also, Plesk does not support dist-upgrading a Debian-like system (such as Ubuntu) as of this moment. You have to perform a server to server mgration using Plesk's migration manager.

Thank you for your help.
I spent a good deal of this weekend (it was rainy anyhow) trying to downgrade, dpkg -i and whatnot to get apache and the entire install back to the pre-apt-get dist-upgrade. I tried to install specific versions, give apt preferences, ppa-purge for removing all newly installed packages and go back to vanilla. no luck.

apt-get alway wanted to deinstall all psa* packages. So now I will have to revert to getting a costly backup played back in. My hoster provides daily tape backups for a fee, so that is what I'll have to do now, sadly.
Seems like that the dist-upgrade changed a lot of dependencies and untangling that mess would take, me at least, a very long time.

Cheers