TurnKey Linux Virtual Appliance Library

Example usage scenario

Alon wants to refresh all TurnKey Linux appliances with the latest security updates.

He writes a script which accepts the name of an appliance as an argument, downloads the latest version from Sourceforge, extracts the root filesystem, installs the security updates, repackages the root filesystem into an appliance ISO and uploads a new version of the appliance back to Sourceforge.

After testing the script on his local Ubuntu workstation, he asks the Hub to launch a new TurnKey Core instance (, transfers his script and installs whatever dependencies are required. Once everything is tested to work, he creates a new TKLBAM backup with captures the state of his master worker server.

Alon runs his first cloudtask test:

echo core | cloudtask --workers= refresh-iso-security-updates

Once he confirms that this single test job worked correctly, he's ready for the big batch job that will run on 10 servers in parallel.

Since this is a routine task Alon expects to repeat regularly, he creates a pre-configured cloudtask template for it in $HOME/cloudtasks:

$ mkdir $HOME/cloudtasks
$ cd $HOME/cloudtasks

$ cat > refresh-iso << 'EOF'
from cloudtask import Task

class RefreshISO(Task):
    DESCRIPTION = "This task refreshes security updates on an ISO"
    BACKUP_ID = 123
    COMMAND = 'refresh-iso-security-updates'
    SPLIT = 10
    REPORT = 'mail: cloudtask@example.com alon@example.com liraz@example.com'




$ chmod +x ./refresh-iso

$ cat $PATH_LIST_APPLIANCES | ./refresh-iso
About to launch 10 cloud servers to execute the following task:

  Parameter       Value
  ---------       -----

  jobs            40 (appengine .. zimbra)
  command         refresh-iso-security-updates
  hub-apikey      5YGVPEMHJHU5EA
  ec2-region      us-east-1
  ec2-size        m1.small
  ec2-type        s3
  user            root
  backup-id       123
  workers         -
  overlay         -
  post            -
  pre             -
  timeout         -
  report          mail: cloudtask@turnkeylinux.org liraz@turnkeylinux.org

Is this really what you want? [yes/no] yes

session 11 (pid 29709) (29721): launched new worker (29722): launched new worker (29724): launched new worker (29723): launched new worker


45 minutes later, Alon receives an e-mail from cloudtask that the job has finished. In the body is the session log detailing if errors were detected on any job (e.g., non-zero exitcode), how long the session took to run, etc.

Had he wanted to, Alon could have followed the execution of the task jobs in real-time by tailing the worker log files:

tail -f ~/.cloudtask/11/workers/29721