Posted in Uncategorized on May 30th, 2016
My colleague Matthew gave a presentation about bare metal provisioning servers at Facebook on IPv6-only networks at SREcon last month. He discusses the entire process from why we went v6-only, selection of DHCP server and network boot loaders, through installing CentOS on hosts, and all of the gotchas along the way. By audience survey it […]
Posted in Uncategorized on May 2nd, 2016
It turns out my SuperMicro A1SAI boards made a fucking liar out of me. I bitched and moaned it was 2016 and they didn’t support UEFI PXE booting despite supporting UEFI, but they do. I just didn’t know where to look. Under “PCIe/PCI/PNP Configuration” in boot setup, the “Launch Storage OpROM Policy” and “Launch Network OpROM […]
Posted in Uncategorized on Apr 9th, 2016
If you have Mellanox ConnectX-3 or ConnectX-4 NICs in your servers, I discovered it’s possible to do IPv6 OS installations via PXE. FlexBoot is their on-board PXE implementation that ships on their NICs and it’s based on iPXE. It turns out that as of FlexBoot version 3.4.718 from January 2016 they’ve added beta IPv6 support. […]
Posted in Uncategorized on Jan 11th, 2010
My Nagios boxes run pnp4nagios+npcd to record plug-in performance data to RRD files. On one system I enabled rrdcached on, a little over 9,000 files are updated every five minutes. I saw a 30% decrease in disk write operations/second, all other things held constant. There wasn’t a noticeable difference in bytes/second, which I guess is […]
Posted in Uncategorized on Jan 9th, 2010
I was excited to see that rrdtool 1.4 was finally released (in October), and with it rrdcached support finally in a main release. After updating rrdtool packages on a couple of my systems I sat out to make things start using the new caching daemon. Cacti was my first to play around with since it […]
Posted in Uncategorized on Dec 18th, 2009
It turns out my problems with IPv6-only Net-SNMP wasn’t a problem with snmpd, it was a problem with selinux. After starting with -Dread_config -c /etc/snmp/snmpd.conf it became apparent: snmpd[9026]: registered debug token read_config, 1 snmpd[9028]: /etc/snmp/snmpd.conf: Permission denied snmpd[9028]: /etc/snmp/snmpd.conf: Permission denied snmpd[9028]: Warning: no access control information configured. It’s unlikely this agent can serve […]
Posted in Uncategorized on Dec 4th, 2009
[root@nicky bin]# /sbin/ifconfig -a eth0 Link encap:Ethernet HWaddr 00:16:3E:69:8E:99 inet6 addr: fe80::216:3eff:fe69:8e99/64 Scope:Link inet6 addr: 2a01:348:0:6:5d59:506a:0:1/64 Scope:Global UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 I turned off IPv4 completely on nicky and suddenly realized a few things: NTP: There’s no v6 NTP servers in the rhel.pool.ntp.org pools. Wound up using Sixxs.net’s pool. CentOS repositories: There’s not […]
