This section describes what typically comprises an ONOS test environment, and how to manage multiple ONOS instances using cells and utility scripts.
|This page assumes that the reader has been able to work through Installing and Running ONOS.|
Testing and managing a distributed platform like ONOS can become a cumbersome task.
In order to simplify testing and to make it more repeatable, a number of assets, including the aforementioned ONOS scripts, have been developed to make the developer’s and tester’s lives easier. These are located under onos/tools/test/, and Appendix A of this Guide provides a listing of available utilities.
An ONOS developer's environment may include the following:
In the above case, the ONOS scripts are run from the development machine, and are directed towards the VMs running on a hypervisor (which can also be on the same machine, or elsewhere).
Lastly, since a developer may want to test different scenarios against different sets of VMs or servers, ONOS provides the notion of test cells.
A test cell refers to a specific controller cluster environment designated for testing. This can mean a set of bare-metal servers, or a set of VMs running on developer’s laptop. Cell definition files are bash snippets that export a few environment variables into the developer’s (or tester’s) shell. These variables are then used by a number of the ONOS test and utility scripts. This allows the scripts and test scenarios to be independent to a specific test bench setup.
Cell definitions are loaded into the shell environment with the
cell utility. This utility takes the name of a cell definition file as the argument. For example:
$ cell local ONOS_CELL=local OCI=192.168.56.101 OC1=192.168.56.101 OC2=192.168.56.102 OCN=192.168.56.103 ONOS_FEATURES=webconsole,onos-api,onos-core,onos-cli,onos-openflow,onos-gui,onos-rest,onos-app-fwd,onos-app-proxyarp,onos-app-tvue ONOS_NIC=192.168.56.*
cell echoes back with the key environment variables understood by the ONOS scripts:
Once a cell definition is exported, utilities such as
onos will fall back to using the value set in
OCI (192.168.56.101 for above) if not given any parameters.
The utility script
cells can be used to view all available cell definitions. Without parameters,
cell will list the values associated with the current cell in use
A cell definition file defines values for the aforementioned environment variables. A cell definition file may look like the following:
# Default ONOS Controller VM instances 1,2,3 and a Mininet VM export OC1="192.168.56.101" export OC2="192.168.56.102" export OC3="192.168.56.104" export OCN="192.168.56.103" # Mininet VM # for node clustering export ONOS_NIC=”192.168.56.*” # ONOS features to load export ONOS_FEATURES="webconsole,onos-api,onos-core-trivial,onos-cli"
These files are located in ONOS_ROOT/tools/test/cells/.
ONOS 1.1.0 and later comes with vicell command to ease editing and applying cell definition files. See vicell -h for usage details.
Custom cell definition files may be added to ONOS_ROOT/tools/test/cells/, which enables them to be loaded and listed with
ONOS, being an SDN controller authored in Java, can run on a variety of platforms. However, in the interest of focus, the ONOS team engages primarily in testing on Ubuntu server distributions, specifically Ubuntu Server 14.04* LTS 64-bit.
Additionally, the VMs used for running ONOS instances and Mininet can be configured to better mesh with the functionality of the ONOS utility scripts and the test environment:
scpfor their functions, and this lets one avoid having to type a password each time a script is run.
For password-less login, the
onos-push-keys utility can be used to transfer one's SSH key to the VM.
Once set up, changes to the codebase can be (relatively) quickly tested in a distributed setting as follows:
For step 5, a developer can take advantage of the
OC variables when using
$ onos-install -f $OC1 #install ONOS to OC1
This procedure must be repeated for each target, as
onos-install is only capable of handling one target at a time. In ONOS 1.1.0 and later, the
onos-group command can be used to automatically target all cell member VMs at once:
$ onos-group install -f
Utilities such as
onos-service also take the
--cell argument that enables it to manage all cell members at once. For example, to restart all ONOS instances in a cell:
$ onos-service --cell restart
Finally, a developer may not be able to run multiple VMs due to the resource constraints of their build machine or environment. In such cases, lightweight virtualization technologies may be used to supply the resource containment for each ONOS instance. Multiple instances using LXC demonstrates the use of LXC containers for this purpose.
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