Tag Archive: apache

Server migration

As I’ve been mentioning before, the content is this server (ks26301.kimsufi.com) will be migrated to a new server (ks3291437.kimsufi.com). These are dedicated servers from http://www.isgenoeg.nl. The ks26301 server, which I have been using since April 2009, is their 2008 model. Back in 2009, their services got introduced in the Netherlands, and the first 1000 subscribers got a year free. I was one of the lucky.

Anyhow, this is a server from 2008, and the price hasn’t changed (apart from the taxes, that is). The point is, for the same price they offer much better specs. So, it makes sense to migrate. Also, over the past years I am hosting services for certain people, which makes the configuration I’ve been using since 2011 less optimal. I never enticipated the fact I would be offering hosting services to third parties, so even more reason to migrate my services to a new server.

At this point, I would like to highlight one of the issues that arrises during such a migration, and provide a solution for it. The problem is the way DNS works. When I change my DNS entries, it takes a while to propagate through the internet. The old IP address might be cached at some DNS server and so on. Therefore, during the migration, requests may arrive at both the old and the new server. So, how to make this situation transparant to the user?

First, let’s have a look at Apache. We’re going to use the mod_proxy for this purpose. I had this module already installed on my system, therefore, in my /etc/httpd/conf/httpd.conf I have

LoadModule proxy_module modules/mod_proxy.so
LoadModule proxy_connect_module modules/mod_proxy_connect.so
LoadModule proxy_ftp_module modules/mod_proxy_ftp.so
LoadModule proxy_http_module modules/mod_proxy_http.so
LoadModule proxy_scgi_module modules/mod_proxy_scgi.so
LoadModule proxy_ajp_module modules/mod_proxy_ajp.so
LoadModule proxy_balancer_module modules/mod_proxy_balancer.so

I might check later on a different (non-production) server which of these are actually required for this purpose.

Anyhow, in my /etc/httpd/conf/extra/httpd-vhosts.conf, I use the following to proxy the connection to the new server. Please note my old server resolved the domain.tld to the new server. Just to be sure it won’t get caught up in a loop, I might add it to /etc/hosts as well. (I’ve kept the DocumentRoot in there, but it has no real purpose anymore. Merely a fallback in case the mod_proxy isn’t loaded)

<VirtualHost *:80>
  ServerAdmin webmaster@domain.tld
  DocumentRoot "/path/to/documentroot"
  ServerName domain.tld
  ServerAlias www.domain.tld
  ErrorLog "/var/log/httpd/domain.tld-error_log"
  CustomLog "/var/log/httpd/domain.tld-access_log" combined

  <IfModule mod_proxy.c>
    <Proxy *>
      Order deny,allow
      Allow from all
    ProxyRequests off
    ProxyPassInterpolateEnv On
    ProxyPass / http://www.domain.tld/ interpolate


Next issue, is incoming mail. For now, I start at migrating the websites, and later I will migrate the mail. But as a proof-of-conecpt, I have tested this for one domain which only has a catch-all-forward.

The ks26301 runs exim as smtp server, well, basically, we’re going to tell it to forward mail for the specific domain to the ks3291437 server.

Just below begin routers in the /etc/mail/exim.conf file, we add

  driver = manualroute
  domains = "domain.tld"
  transport = remote_smtp
  route_list = * ks3291437.kimsufi.com

These configurations should make the transition to the new server transparant to the end-user.

My server Pi, well… it still needs some server stuff to be installed. Installing git has been forever on my TODO list. One of the things that are supposed to be handles by this git server is nightly backups of my dedicated server, which hosts this blog among a number of other sites. Originally, my BeagleBoard was supposed to have this role, but due its instabilities, I have never set it us as a git server. At some point in time, Eileen wanted to set up a server at her place, and asked me to help her with configuring it. So I asked if I could have some space on that server for backup purposes. Unfortunately, that machine was unstable as well, so it shut down as well.

To manage git, we’re going to use gitosis. The very same way as is done on my dedicated server (at ovh). But we’re going to use a different configuration. The ovh server exports all repositories, while here we’re going to set up private repositories. But we also want to have the possibility to have public repositories. We will also configure gitweb to have a nice interface to those public repositories.

This configuration is performed on a Raspberry Pi running ArchLinuxARM. However, this guide could be applied to regular ArchLinux on i386 or x86_64 as well.

Let’s get started, shall we?

[andre@rpi-server ~]$ yaourt -S gitosis-git

We have to create set the home directory for the git user manually:

[root@rpi-server home]# mkdir /srv/gitosis
[root@rpi-server home]# usermod -d /srv/gitosis/ git

Since we’re hosting this on a raspberry pi, and don’t want to store the repository on the SD Card, we’re going to apply the same method as we’re dong during the setup of the NFS shares: We add the following line to our fstab

/home/gitosis   /srv/gitosis    none    bind    0   0

Which basically means we mount the /home/gitosis directory to /srv/gitosis. Of course we could simple have made a symlink as well. Anyhow, let’s continue.
***** TODO **** use a symlink after all???

[root@rpi-server home]# mkdir /srv/gitosis
[root@rpi-server home]# mkdir /user/gitosis
[root@rpi-server home]# mkdir /srv/gitosis
[root@rpi-server home]# chown git:git /srv/gitosis
[root@rpi-server home]# chown git:git /home/gitosis/
[root@rpi-server home]# mount /srv/gitosis

Now, I am going to initialise gitosis. I will do this as the git user. So, I su to root and then to git, like this:

[andre@hplaptop ~]$ su
[root@hplaptop andre]# su git
[git@hplaptop andre]$ cd
[git@hplaptop /]$ 

I have placed a file in the home folder containing my public key. I will try to initialise gitosis using this key:

[git@rpi-server gitosis]$ gitosis-init < andre\@hp.pub 
fatal: unable to access '/home/andre/.config/git/config': Permission denied
Traceback (most recent call last):
  File "/usr/bin/gitosis-init", line 9, in 
    load_entry_point('gitosis==0.2', 'console_scripts', 'gitosis-init')()
  File "/usr/lib/python2.7/site-packages/gitosis/app.py", line 24, in run
    return app.main()
  File "/usr/lib/python2.7/site-packages/gitosis/app.py", line 38, in main
    self.handle_args(parser, cfg, options, args)
  File "/usr/lib/python2.7/site-packages/gitosis/init.py", line 136, in handle_args
  File "/usr/lib/python2.7/site-packages/gitosis/init.py", line 75, in init_admin_repository
    template=resource_filename('gitosis.templates', 'admin')
  File "/usr/lib/python2.7/site-packages/gitosis/repository.py", line 54, in init
    raise GitInitError('exit status %d' % returncode)
gitosis.repository.GitInitError: exit status 128

Apparently, it tries to access file in my (andre) home directory, while its running as git. It shouldn’t know about me, right? Well….

[git@rpi-server gitosis]$ set | grep andre

So, there is still a reference to my config directory in the enviorement, lets unset this shit and continue:

[git@rpi-server gitosis]$ unset XDG_CACHE_HOME
[git@rpi-server gitosis]$ unset XDG_CONFIG_HOME
[git@rpi-server gitosis]$ unset XDG_DATA_HOME

Now, we can initialise gitosis:

[git@rpi-server gitosis]$ gitosis-init < andre\@hp.pub 
Initialized empty Git repository in /srv/gitosis/repositories/gitosis-admin.git/
Reinitialized existing Git repository in /srv/gitosis/repositories/gitosis-admin.git/

Now, we're going to install and configure the web server:

[andre@rpi-server ~]$ yaourt -S apache

We're going to do the mount bind again

/home/http   /srv/http    none    bind    0   0
[root@rpi-server ~]# mkdir /home/http
[root@rpi-server ~]# mount /srv/http/
[root@rpi-server ~]# chown http:http /srv/http/
[root@rpi-server ~]# chmod g+w /srv/http/

I'm going to add myself to the http group.

[root@rpi-server http]# groupmems -a andre -g http

As I've mentioned before, I wish to host gitweb as well. Gitweb is in the git package, so it's already installed, just making a symlink is enough, which I can do as myself, as I am in the group http. I've also downloaded the "unknown" folder from my ovh server, which is the page that displays the "domain not served as this server" page in case an unknown vhost is requested. I will move this as well:

[andre@rpi-server ~]$ ln -s /usr/share/gitweb /srv/http/gitweb
[andre@rpi-server ~]$ mv unknown /srv/http

As the fact I am putting my "unknown vhost" page on this server, it will be supporting vhosts. If a requested domain doesn't match any VirtualHost in the apache config file, it will serve the first entry in the config file, therefore we will edit the config file /etc/httpd/conf/extra/httpd-vhosts.conf and put the following in

NameVirtualHost *:80

<VirtualHost *:80>
    DocumentRoot "/srv/http/unknown"
    ErrorLog "/var/log/httpd/unknown-error_log"
    CustomLog "/var/log/httpd/unknown-access_log" combined

However, Virtual Hosts aren't enabled yet. We need to edit the main config file in order to include the vhosts config file. We need to open /etc/httpd/conf/httpd.conf and uncomment the virtual hosts line:

# Virtual hosts
Include conf/extra/httpd-vhosts.conf

The "unkown vhost" page is written in php, so we're also going to install php:

[andre@rpi-server ~]$ yaourt -S php-apache 

And add it to the apache main configuration file again: we need to load the library, and include the configuration file:

LoadModule php5_module modules/libphp5.so
Include conf/extra/php5_module.conf

We also have to add something for the gitweb configuration to the config file

<Directory "/srv/http/gitweb">
   DirectoryIndex gitweb.cgi
   Allow from all
   AllowOverride all
   Order allow,deny
   Options ExecCGI
   <Files gitweb.cgi>
   SetHandler cgi-script
   SetEnv  GITWEB_CONFIG  /etc/conf.d/gitweb.conf

To finish the configuration, we're going to add an actual virtual host to the config, which also serves the gitweb. So we're going to edit the vhosts config again:

<VirtualHost *:80>
    ServerName ehv.blaatschaap.be
    Alias /gitweb "/srv/http/gitweb" 
    DocumentRoot /srv/http/blaatschaap.be/ehv
    ErrorLog "/var/log/httpd/blaatschaap.be-ehv-error_log"
    CustomLog "/var/log/httpd/blaatschaap.be-ehv-access_log" combined
    <Directory /var/www/gitweb>
       Options ExecCGI +FollowSymLinks +SymLinksIfOwnerMatch
       AllowOverride All
       order allow,deny
       Allow from all
       AddHandler cgi-script cgi
       DirectoryIndex gitweb.cgi

Now, this part of the server is configured. What still has to be done is putting the backup repository so far on the Pi server, and adjusting the script on the ovh server to make backups to this server.

Also, pretty soon I will be getting a new OVH server, as they're offering much better specs for the same price, and I am going to convert to Debian for a server. ArchLinux is great for desktops, but the changed in a rolling distribution such as ArchLinux are not convinient for a machine that's supposed to be always up. Especially the transition from sysvinit to systemd is giving me a headache, as sysvinitscripts are no longer supported... and I am a bit uncomfortable about chaging stuff in the boot loader as I don't have any serial console or anything. If it reboots, I just have to wait till it comes up, if it doesn't.... bad luck.

Besides, I am hosting a few sites for third parties. In order to keep overview, and offer my users a convenient interface I am considering usingISPconfig on my new server. As I have paid for the current server till 15 April, I should have finished the transition by then. I have paid till April since I have renewed my contract just one day before the VAT was increased from 19% to 21%. Anyhow. I plan to order the new server in February, so I have plenty of time for testing.