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Using HTCondor Annex for the First Time

We assume you already have an AWS account, as well as a log-in account on a Linux machine with an administrator who's willing to open a port for you. If so, you can follow the instructions for UsingCondorAnnexForTheFirstTime.

What You'll Need to Know

To create a HTCondor annex with on-demand instances, you'll need to figure out four things:

  1. A name for it. "MyFirstAnnex" is a fine name for your first annex.
  2. Which instance type you want to use. Each type of instance has a different number (and type) of CPU cores, amount of RAM, size of local storage, and the like. If you're not sure, we recommend starting with 'm4.large', which has 2 CPU cores and 8 GiB of RAM.
  3. How many instances you want. For your first annex, when you're checking to make sure things work, you may only want one instance.
  4. The duration of the annex, expressed as a whole number of seconds. Twenty minutes (1200 seconds) should be long enough to make sure things are working, but since AWS charges by the whole hour, you may as well ask for fifty minutes, instead (3000 seconds).

condor_annex will arrange for your annex's instances to be terminated after its duration has passed. Once it's in place, this lease doesn't depend on your machine, but it's only checked every five minutes, so give your deadlines a lot of cushion to make you don't get charged for an extra hour.

Start an Annex

If you agree with the suggestions above, entering the following will start an annex. 

$ condor_annex -duration 3000 -count 1 -annex-name MyFirstAnnex -odi-instance-type m4.large
MyFirstAnnex[something-something-something]

This command will return after HTCondor has set up the 3000-second (50 minute) lease and requested that Amazon start 1 instance. The output can be used on AWS to identify annex instances; you won't have to do that unless something goes wrong.

Monitor your Annex

You can find out if that instance has successfully joined the pool in the following way. 

$ condor_status -annex MyFirstAnnex
slot1@ip-172-31-48-84.ec2.internal  LINUX     X86_64 Unclaimed Idle 0.640 3767
slot2@ip-172-31-48-84.ec2.internal  LINUX     X86_64 Unclaimed Idle 0.640 3767

              Total Owner Claimed Unclaimed Matched Preempting Backfill  Drain
 X86_64/LINUX     2     0       0         2       0          0        0      0
        Total     2     0       0         2       0          0        0      0

This example shows that the annex instance you requested has joined your pool. (The default annex image configures one static slot for each CPU it finds on start-up.)

Stop an Annex

The following command shuts HTCondor off on each instance in the annex; if you're using the default annex image, doing so causes each instance to shut itself down. 

$ condor_off -master -annex MyFirstAnnex
Sent "Kill-Daemon" command for "master" to master ip-172-31-48-84.ec2.internal