f5p

Lightweight job scheduler and daemon for nanopore data processing on a mini-cluster

pre-requisites

• A compute-cluster composed of devices running Linux connected to each other preferably using Ethernet.
• One of the devices will act as the head node to issue commands to other worker nodes.
• A shared network mounted storage for storing data.
• SSH key based access from head node to worker nodes.
• Optionally you may configure ansible to automate configuration tasks.

getting started

Building and initial configuration

1. First build the scheduling daemon (f5pd) and client (f5pl)

make

2. Scheduling client (f5pl) is destined for the head node. Copy the scheduling daemon (f5pd) to all worker nodes. If you have configured ansible, you adapt the following command.

ansible all -m copy -a "src=./f5pd dest=/nanopore/bin/f5pd mode=0755"

3. Run the scheduling daemon (f5pd) on all worker nodes. You may want to add (f5pd) as a systemd service that runs on the start-up. See scripts/f5pd.service for an example systemd configuration and scripts/install_f5pd_service.sh for an example script.

4. On the head node create a file containing the list of IP addresses of the worker nodes, one IP address per line. An example is in data/ip_list.cfg.

5. Optionally, you may install a web server on the head node and host the scripts under scripts/front to view the log on a web-browser. You will need to edit the paths in these scripts to point to the log location. Note that these scripts are not probably safe to be hosted on a public server.

Running for a dataset

1. Modify the shell script scripts/fast5_pipeline.sh for your use-case. This script is to be called on worker nodes by (f5pd), each time a data unit is assigned. The example script:

• takes a location of a tar file on the network mount (which contains a batch of fast5 files) as the argument;
• deduce the location of fastq file on the network mount associated to the tar file;
• copy the tar file and fastq file to the local storage;
• runs a methylation-calling pipeline that uses the tools minimap2, samtools and nanopolish; and,
• copy the results back to the network mount.

Note that this scripts should exit with a non zero status if any thing went wrong. After modifying the script, copy it to the worker nodes to the location /nanopore/bin/fast5_pipeline.sh

2. On the head node create a file containing the list of tar files (each tar file contains a fast5 batch), one tar file per line. An example is in data/file_list.cfg.

3. Launch the f5pl with the IP list and the tar file list you previously created as the arguments.

./f5pl data/ip_list.cfg data/file_list.cfg

You may adapt the script scripts/run.sh which performs a run discussed above.