Last Updated: February 25, 2016
· jpkrohling

Building your own mirror

When hosting services at home, one comon scenario is that all the VMs have the same OS and the same basic software, with a few differences between them. This means that, if you have 7 VMs (as it's my case), you'd download the same updates 7 times. While this is not a big problem for the day-to-day, it becomes a hassle when you decide to upgrade your VMs. Downloading hundred of packages, or even booting a new VM, becomes a task that takes some time to finish.

Tired of this, I've decided to build a simple mirroring server. I'm using nginx and squid for that. Simply put, that's all one needs:

For nginx, on Fedora 20:

yum install nginx squid
firewall-cmd --add-port=80/tcp --permanent
firewall-cmd --add-port=443/tcp --permanent
firewall-cmd --add-port=80/tcp
firewall-cmd --add-port=443/tcp

And on /etc/squid/squid.conf:

maximum_object_size 4 GB
http_port 3128 accel
cache_peer parent 80 0 no-query originserver
http_access allow all
cache_dir ufs /var/spool/squid 161166 16 256
access_log /var/log/squid/access.log

On /etc/nginx/conf.d/mirror.conf:

server {
    listen 80;
    location / {
        proxy_set_header X-Forwarded-Host $host;
        proxy_set_header X-Forwarded-Server $host;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_pass http://localhost:3128/;

After that, all you need is to point your machines to use this host when getting updates. This can be done by changing the /etc/yum.repos.d/fedora*repo files, to use the URL from your mirror as baseurl, instead of using a metalink.

And when you decide to boot new VMs, you can also take advantage of this mirror, using the "-l" parameter on virt-install, pointing to the os directory on your mirror, like this:

virt-install --ram 1024 -l --os-type=linux --os-variant=fedora20 --disk path=/usr/local/data/projects/virtual-images/NAME.qcow2,format=qcow2 --vnc --name NAME