If you don’t like this government, it won’t last forever.

By , 2014年9月19日 6:01 下午



“If you don’t like me, I wont’ be here forever. If you don’t like this government, it won’t last forever.”

This is the best sentence I’ve heard regarding country, government, politicians, and people. It is so simple, and so true.



By , 2014年9月18日 6:37 下午





Pegasus / Montage workflow on Amazon Web Services

By , 2014年9月16日 8:06 下午

I took some notes while going through Mats Rynge’s tutorial on “Pegasus / Montage workflow on Amazon Web Services“. The tutorial if officially available at the following URL, but the content is far from complete. I managed to finished this tutorial, and thought that my experience might be valuable for someone else out there in the dark.


Step 1. Launch an EC2 instance

In the Oregon region, launch an EC2 instance with AMI ami-f4e47cc4. It is recommend that you use the same security group for all EC2 instance to be launched in the Condor cluster. Also, in the security group, all communication between all EC2 instances using the same security group.

SSH into the instance using the following command:

ssh -i keypair.pem montage@IP
cd .ssh
cat id_rsa.pub >> authorized_keys
cd ~

Step 2. Configure Condor

Edit /etc/condor/config.d/20_security.conf,update ALLOW_WRITE and ALLOW_READ to the IP range of your VPC. For example, if the IP range of your VPC is, then you can set “ALLOW_WRITE = 172.31.*” and “ALLOW_READ = 172.31.*”. Then you need to restart Condor with the following command:

sudo service condor restart

Step 3. Create a Montage workflow

mkdir workfow
cd workflow
mDAG 2mass j M17 0.5 0.5 0.0002777778 . file://$PWD file://$PWD/inputs

Step 4. Pegasus Related

cd ~/etc
cp ../workflow/replica.catalog .
cp ../workflow/dag.xml .

Step 5. Update site.xml with the following content


Step 6. Plan the workflow

pegasus-plan --conf pegasus.conf --dax dag.xml

Step 7. Run the workflow

pegasus-run  /home/montage/etc/montage/pegasus/montage/run0001

Step 8. Monitor the workflow

pegasus-status -l /home/montage/etc/montage/pegasus/montage/run0001
tail montage/pegasus/montage/run0001/jobstate.log

The last command is very nice in that you can see what is currently being run. Please note that you need to replace the path with the actual path given to you by Pegasus.

That’s all. After spending weeks searching over the Internet, everything now seems to be simple.


By , 2014年9月1日 12:48 下午



最近6 个月来读到的最好的一本书。


Panorama Theme by Themocracy