Through some Google-fu and some other great tutorials, I’ve successfully setup a groups of Redis machines with automatic failover detection via keepalived and sentinel. This sounds mundane, but lets you setup another layer of protection for your Redis cluster without lots of extra configuration.
Not too long ago in the Linux world, firewall rules were complex. iptables did its job very well, but managing rules was daunting for a newcomer. Debian 9 introduces some changes that make it pretty simple to add a firewall rule.
One of the new tools I’ve discovered is Chef to manage the configuration and software on Storehouse’s fleet of virtual machines. Chef makes it really handy to update and track config changes, since everything can be tracked using Git or similar. One issue we ran into was having `chef-client` run at the same time for multiple machines.
This is a pretty straightforward thing I’ve wanted to do for some time. Basically, I have a number of sites that I use internally that I wanted to get certificates via Let’s Encrypt, but I also wanted to keep them restricted to only a few IP addresses. The solution is quite simple and works perfectly.
A subtle issue I ran into was the issue that Proxmox VE would sometimes unmount a GlusterFS volume and would fail to backup. This issue was a bit sneaky though, since the PVE backup program wouldn’t execute it wouldn’t send an email notifying me of the failure. This would make it so the backups would fail silently for some time, until I happened to login and see the errors in the cluster’s log.