The process for configuring Memcached on the Ubuntu virtual machine in Vagrant is different from the process for configuring Memcached on a normal Ubuntu installation.
The provisioning script installed Memcached and libmemcached-0.53 on the system. If you plan to configure Memcached, you will need to test the Memcached installation.
In the virtual machine, switch to the /vagrant/makahiki directory and run some commands in the manage.py shell:
vagrant@precise32:~$ sudo service memcached restart
vagrant@precise32:~$ export LD_LIBRARY_PATH_OLD=$LD_LIBRARY_PATH
vagrant@precise32:~$ export LD_LIBRARY_PATH=/usr/local/lib:/usr/lib:$LD_LIBRARY_PATH
vagrant@precise32:~$ export MAKAHIKI_USE_MEMCACHED=True
vagrant@precise32:~$ cd /vagrant/makahiki
vagrant@precise32:/vagrant/makahiki$ ./manage.py shell
Python 2.7.3 (default, Apr 10 2013, 05:46:21)
[GCC 4.6.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>> from django.core.cache import cache
>>> cache
<django_pylibmc.memcached.PyLibMCCache object at 0x8c93c4c>
>>> cache.set('test','Hello World')
True
>>> cache.get('test')
'Hello World'
>>> exit()
vagrant@precise32:/vagrant/makahiki$ unset MAKAHIKI_USE_MEMCACHED
vagrant@precise32:/vagrant/makahiki$ export LD_LIBRARY_PATH=$LD_LIBRARY_PATH_OLD
vagrant@precise32:/vagrant/makahiki$ unset LD_LIBRARY_PATH_OLD
vagrant@precise32:/vagrant/makahiki$ sudo service memcached stop
Stopping memcached: memcached.
If running “manage.py shell” causes the error:
django.core.cache.backends.base.InvalidCacheBackendError: Could not import pylibmc.
then the LD_LIBRARY_PATH may not be set correctly in makahiki_env.sh. This error occurs when MAKAHIKI_USE_MEMCACHED=True but LD_LIBRARY_PATH does not include the location of pylibmc.
If any of the following errors occur, then Memcached is not working:
- cache prints a blank to the console, or cache is a “django.core.cache.backends.dummy.DummyCache object.”
- cache.set returns False.
- cache.get returns False or causes a segmentation fault.
If so, make sure environment variables are set and Memcached is running.
Memcached is a backend cache for the Makahiki web server. Configuring memcached is optional.
Run /vagrant/vagrant/makahiki_env_memcached_append.sh to add some code to the end of the /home/vagrant/makahiki_env.sh file:
vagrant@precise32:~$ sh /vagrant/vagrant/makahiki_env_memcached_append.sh
If the file is the same as the one created by the bootstrap.sh script, lines will be appended automatically, with the result [Succeeded].
If the makahiki_env_memcached_append.sh script has been run already but no changes have been made, the script will do nothing and output the result [Already completed].
If you have made other changes to makahiki_env.sh between the time the virtual machine was created and now, the script will ask permission to append to the file instead of copying over it:
WARNING! /home/vagrant/makahiki_env.sh file is different from expected file.
Append settings anyway? (Result may contain duplicate lines.) [Y/n]
If you answer n the script’s result will be [Cancelled]. Answer Y to add these lines to the end of makahiki_env.sh:
export MAKAHIKI_USE_MEMCACHED=True
# Don't add libmemcached paths more than once
if [ ! $LIBMEMCACHED_PATHS_ADDED ];
then
export LD_LIBRARY_PATH=/usr/local/lib:/usr/lib:$LD_LIBRARY_PATH
export LIBMEMCACHED_PATHS_ADDED=True
fi
If the operation succeeds, the result will be [Succeeded].
Source /home/vagrant/.bashrc to apply changes:
vagrant@precise32:~$ source /home/vagrant/.bashrc
On Vagrant, the memcached service should run automatically once installed by the provisioning script. If it does not run, start it manually:
vagrant@precise32:~$ sudo service memcached start
On Ubuntu, the memcached service should run automatically at startup.
To test this, shut down the virtual machine, then restart it:
vagrant@precise32:~$ sudo shutdown -h now
-- output omitted --
Connection to 127.0.0.1 closed by remote host.
Connection to 127.0.0.1 closed.
> vagrant up --no-provision
-- output omitted --
> vagrant ssh
Warning
Do not use sudo shutdown -r now in Vagrant. This will restart the virtual machine without mounting the /vagrant shared folder.
After the restart, you should be able to test memcached without setting any environment variables:
vagrant@precise32:~$ cd /vagrant/makahiki
vagrant@precise32:/vagrant/makahiki$ ./manage.py shell
Python 2.7.3 (default, Apr 10 2013, 05:46:21)
[GCC 4.6.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>> from django.core.cache import cache
>>> cache
<django_pylibmc.memcached.PyLibMCCache object at 0x8c93c4c>
>>> cache == None
False
>>> cache.set('test','Hello World')
True
>>> cache.get('test')
'Hello World'
>>> exit()
If this test works, then the memcached service is running and will be used by Makahiki.
To disable memcached, edit makahiki_env.sh to set MAKAHIKI_USE_MEMCACHED=False and comment out LD_LIBRARY_PATH settings:
export MAKAHIKI_USE_MEMCACHED=False
# Don't add libmemcached paths more than once
#if [ ! $LIBMEMCACHED_PATHS_ADDED ];
# then
# export LD_LIBRARY_PATH=/usr/local/lib:/usr/lib:$LD_LIBRARY_PATH
# export LIBMEMCACHED_PATHS_ADDED=True
#fi
Then stop the memcached service, and stop it from running at startup:
vagrant@precise32:~$ sudo service memcached stop
vagrant@precise32:~$ sudo update-rc.d -f memcached disable
The memcached service will no longer be used by Makahiki, and will no longer run at startup.
To test this, shut down the virtual machine, then restart it:
vagrant@precise32:~$ sudo shutdown -h now
-- output omitted --
Connection to 127.0.0.1 closed by remote host.
Connection to 127.0.0.1 closed.
> vagrant up --no-provision
-- output omitted --
> vagrant ssh
After starting the new SSH session, test memcached once again:
vagrant@precise32:~$ cd /vagrant/makahiki
vagrant@precise32:/vagrant/makahiki$ ./manage.py shell
Python 2.7.3 (default, Apr 10 2013, 05:46:21)
[GCC 4.6.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>> from django.core.cache import cache
>>> cache
<django.core.cache.backends.dummy.DummyCache object at 0x964b72c>
>>> cache.set('test','Hello World') == None
True
>>> exit()
vagrant@precise32:/vagrant/makahiki$
Cache should be a DummyCache, and cache.set('test','Hello World') == None should return True.
Edit makahiki_env.sh to set MAKAHIKI_USE_MEMCACHED=True, and uncomment the LD_LIBRARY_PATH settings:
export MAKAHIKI_USE_MEMCACHED=True
# Don't add libmemcached paths more than once
if [ ! $LIBMEMCACHED_PATHS_ADDED ];
then
export LD_LIBRARY_PATH=/usr/local/lib:/usr/lib:$LD_LIBRARY_PATH
export LIBMEMCACHED_PATHS_ADDED=True
fi
Source ~/.bashrc to apply the changes:
vagrant@precise32:~$ source ~/.bashrc
Start the memcached service, and set it to run at startup:
% sudo service memcached start
% sudo update-rc.d -f memcached enable