HAProxy in front of Ceph Manager dashboard

The Ceph Mgr dashboard plugin allows for an easy dashboard which can show you how your Ceph cluster is performing. In certain situations you can’t contact the Mgr daemons directly and you have to place a Proxy server between your computer and the Mgr daemons. This can be done easily with HAProxy and the following […]

VXLAN with VyOS and Ubuntu 18.04

VXLAN Virtual Extensible LAN uses encapsulation technique to encapsulate OSI layer 2 Ethernet frames within layer 4 UDP datagrams. More on this can be found on the link provided. For a Ceph and CloudStack environment I needed to set up a Proof-of-Concept using VXLAN and some refurbished hardware. The main purpose of this PoC is […]

Ceph Monitors are laggy or clock might be skewed

This weekend I got to investigate a Ceph cluster which had issues where the Monitors were constantly performing new elections. After some investigation on of the three monitors was eating 100% CPU on a single core and kept printing this in the logs: mon.charlie@2(peon).paxos(paxos updating c 106399655..106400232) lease_expire from mon.0 [2a00:XXX:121:XXX::6789:1]:6789/0 is 2.380296 seconds in […]

Calculating RADOS objects for RBD images

Ceph’s RBD (RADOS Block Device) is just a thin wrapper on top of RADOS, the object store of Ceph. It stripes (by default) over 4MB objects in RADOS. It’s very simple to calculate which RADOS object corresponds with which sector on your RBD image/block device. First you have to find out the block device’s object […]