The more and more I play around with KVM virtualization, the more I realize just how useful Linux bridging is. In the Linux bridging world, a bridge device simulates a multiport Ethernet switch. To connect to the switch, you create a tap device that simulates a port on that switch. Once you have bridging configured [...]
As I mentioned in a previous post, I spent some time trying to get the NetworkManager to respect my custom DNS settings. When I was looking into this issue, I learned about the nm-tool utility. This nifty tool will print the status of each NetworkManager managed interface, as well as the connection state: $ nm-tool [...]
I recently switched my work Desktop from Ubuntu to Fedora 11, and noticed that there are some new configuration options now that network intefaces are managed by the NetworkManager process. Two useful options are the ability to specify the DNS servers and search domains in the network-scripts files, and have those applied when a DHCP [...]
When I was playing around with KeepAlived, I managed to create a few HA scenarios that mirrored actual production uses. One scenario was creating a highly available router, which would forward IPv4 traffic between interfaces. To configure a CentOS or Fedora Linux host to forward IPv4 traffic, you can set the “net.ipv4.ip_forward” sysctl to 1 [...]
I have been assisting a friend with tuning his Netbackup installation. While debugging the source of his issues, I noticed that several jobs were reporting low throughput numbers. In each case the client was backing up a number of large files, which should have been streamed at gigabit Ethernet speeds. To see how much bandwidth [...]
I recently played around with keepalived, and documented my experiences in an article titled Deploying Highly Available Virtual Interfaces With Keepalived. If you are interested in deploying highly available Linux routers, or just looking to failover IP addresses between servers, you may find the article useful.
