The mdbd daemon is a companion to the dominator daemon. It queries one or more Machine DataBases and provides the dominator with information about machines (subs) to manage.
The daemon writes processed and filtered MDB data to a local file
(/var/lib/Dominator/mdb
by default) which the dominator can consume. Thus,
both mdbd and dominator must run on the same machine.
Mdbd is started at boot time, usually by one of the provided init scripts. The mdbd process is baby-sat by the init script; if the process dies the init script will re-start it. It may be stopped with the command:
service mdbd stop
which also kills the baby-sitting init script. It may be started with the comand:
service mdbd start
There are many command-line flags which may change the behaviour of mdbd but many have defaults which should be adequate for most deployments. Built-in help is available with the command:
mdbd -h
The init script reads configuration parameters from the /etc/default/mdbd
file. The following is the minimum likely set of parameters that will need to be
configured.
The USERNAME
variable specifies the username that mdbd should run as.
Since mdbd does not need root privileges, the init script runs
mdbd as this user.
Mdbd requires "upstream" data sources. A configuration file
(/var/lib/Dominator/mdb.sources.list
by default) specifies the data sources
to be collected from.
To directly query AWS for all running instances in a region, you would use the
following configuration file. It will query all the accounts for which you have
API keys in your ~/.aws/credentials
file:
aws-local
An example configuration file which specifies to collect MDB data from CIS
(Cloud Intelligence Service, being developed at Symantec) for the us-east-1
cluster is:
cis http://cis.us-east-1.aws.net:9200/aws/aws_nodes/_search?size=10000
Since CIS is built on top of Elastic Search, the configuration is primarily an Elastic Search query.