Fission is static job scheduling program designed to help you run workloads across multiple machines you have ssh access to. while primarily aimed at container based workloads, arbitrary jobs can be run and managed using fission
accompanying tools will be provided for firewall generation and network setup as well as hooks to tie into existing ip allocation mechanisms
the static nature of fission means it is unable to respond to events such as nodes going down in real time like other software in the same space (mesos, kerbernatues, docker swarm). this can be mitigated to a degree by having your monitoring system invoke or trigger a run of fission on a remote machine. allowing the state of the system to be recalculated and adjusted as required
Like all container software out there, fission makes a mediocre attempt to stay in line with the terminology used by other solutions and invents new terms where appropriate to confuse users
Nodes are simply hosts you have ssh access to that run jobs. Nodes themselves can also be created from jobs for simulating topologies
Jobs are the workload that fission is managing and running across multiple nodes for you. this is generally a container workload but may also be simple program
Facts are used for selecting which nodes are suitable candidates for a particular job, eg some nodes may export a HAS_SSD fact that a high performance disk IO heavy job (eg mysql) may want to select on
If you are using symlinks to templates that expand on the filename (eg collection of jobs) then there may be occasions where you want to override specific facts (eg code or machine upgrades). normally this would involve updating the config file but as this is symlinked you end up affecting all hosts. the solution for this is a ‘.extras’ file containing additional information that is overplayed on the top of the config to allow further customization allowing you to override a subset or all hosts with information to complete the migration before updating the main template
Filters are the counterpart to the tag. These are used by jobs to limit placement decisions. This may be helpful for compliance (credit card processing only on nodes tagged ‘pci-compliant’) or to limit jobs to geographical region
Filters may or may not be used to select based on facts, this is currently undecided due to complexity (ie only on mem > 300MB)
fission uses py.test for testing and supports tox for building the environments. if py.test is not installed system-wide for python 3 then build a virtual environment with the following commands (python 3.4 or newer)
$ python3.4 -m venv venv $ . venv/bin/activate $ pip install pytest
running the tests is then as simple as
$ . venv/bin/activate $ py.test
TODO: Figure out how to actually get changelog content.
Changelog content for this version goes here.