Hello,
I've read some books about Mesos, installed one multi-master cluster
(for POC purposes) with some frameworks (Marathon, Spark for instance)
and watch some talks.
Everything works and my understanding of Mesos is becoming clearer.
However, I'm having a hard time fully understanding this section of the
documentation :
http://mesos.apache.org/documentation/latest/containerizer-internals/
Note :
- my understanding is that Mesos is now heading towards a universal
containerizer, which is able to understand docker (among others) images
thus beeing able to "do some docker" without a docker daemon.
- Also, I don't think Mesos supports nester containers yet either.
But I'm not really sure about what is the mesos-docker-executor, as
opposed to mesos-executor.
- For instance, in the "A)" case of the slave running in a container,
the doc states :
"if the task does not include an executor i.e. it defines a command, the
default executor mesos-docker-executor is launched in a docker container
to execute the command via Docker CLI."
Why Docker CLI ? We are not in a shell context, are we ?
Also, will the command be launched in another docker container,
different from the one running mesos-docker-executor ?
- In the B) case where the slave is not running in a container, the doc
states :
"If task does not include an executor i.e. it defines a command, a
subprocess is forked to execute the default executor
mesos-docker-executor. mesos-docker-executor then spawns a shell to
execute the command via Docker CLI."
Why is the mesos-docker-executor not run in a container ? Also, why does
it not use docker API directly ?
Can you help me figuring out how exactly mesos-docker-executor works and
what its specificality relative to the mesos-executor ?
Thanks
--
Thomas HUMMEL
