Network testing (snap/2.7/CLI)

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Snap CLI ~ UI CLI ~ UI CLI ~ UI
Packages CLI ~ UI CLI ~ UI CLI ~ UI

MAAS provides a comprehensive suite of network and link testing capabilities. MAAS can check whether or not links are connected, detect slow links, and report link and interface speeds via UI or API. In addition, you can test Internet connectivity against a user-provided list of URLs or IP addresses. Bonded NICS will be separated during this testing, so that each side of a redundant interface is fully evaluated.

Network testing also includes customisable network testing and commissioning scripts. There are no particular restrictions on these scripts, allowing you to test a wide variety of possible conditions and situations.

Four questions you may have:

  1. How do I use network link testing?
  2. How can I detect slow network links?
  3. How do I use network validation and testing scripts?
  4. How can I customise network testing?

MAAS can check whether links are connected or disconnected, so that you can detect unplugged cables. If you are not running MAAS 2.7, you must first upgrade and then recommission your machines to find disconnected links. MAAS not only reports unplugged cables, but also gives a warning when trying to configure a disconnected interface. In addition, administrators can change the cable connection status after manually resolving the issue.

To check network testing results, enter the following command:

maas $PROFILE interfaces read $SYSTEM_ID \
| jq -r '(["LINK_NAME","LINK_CONNECTED?","LINK_SPEED", "I/F_SPEED"]
| (., map(length*"-"))), (.[] | [.name, .link_connected, .link_speed, .interface_speed])
| @tsv' | column -t

which produces an output similar to this:

LINK_NAME  LINK_CONNECTED?  LINK_SPEED  I/F_SPEED
---------  ---------------  ----------  ---------
ens3       false            -           1 Gpbs

From this screen, you can see that the ens3 link is not connected (hence an unreported link speed).

Once you have manually repaired the broken connection, an administrator can change cable connection status:

maas $PROFILE interface update $SYSTEM_ID $INTERFACE_ID link_connected=true

As servers and hardware get faster, the chances increase that you might encounter a speed mismatch when connecting your NIC to a network device. MAAS can warn you if your interface is connected to a link slower than what the interface supports, when you run the above command:

maas $PROFILE interfaces read $SYSTEM_ID \
| jq -r '(["LINK_NAME","LINK_CONNECTED?","LINK_SPEED", "I/F_SPEED"]
| (., map(length*"-"))), (.[] | [.name, .link_connected, .link_speed, .interface_speed])
| @tsv' | column -t

From the resulting output, you can detect when your link/interface speeds are slower than expected. Depending on your physical hardware, the problem may not be repairable, but once you identify a slow link, you can replace a slow switch without recommissioning.

Administrators can change or update the link and interface speeds after manual changes
to the connection:

maas $PROFILE interface update $SYSTEM_ID $INTERFACE_ID link_speed=$NEW_LINK_SPEED \
interface_speed=$NEW_INTERFACE_SPEED

Network validation and testing scripts

MAAS allows you to configure network connectivity testing in a number of ways. If MAAS can’t connect to the rack controller, deployment can’t complete. MAAS can check connectivity to the rack controller and warn you if there’s no link, long before you have to try and debug it. For example, if you can’t connect to your gateway controller, traffic can’t leave your network.

Users can now test their network configuration to check for:

  1. Interfaces which have a broken network configuration
  2. Bonds that are not fully operational
  3. Broken gateways, rack controllers, and Internet links

In addition, MAAS can comprehensively test Internet connectivity testing. You can give a list of URLs or IP addresses to check:

In the ephemeral environment, standard DHCP is still applied, but when network testing runs, MAAS can apply your specific configuration for the duration of the test. While all URLs / IPs are tested with all interfaces, MAAS can test each of your interfaces individually, including breaking apart bonded NICS and testing each side of your redundant interfaces. You can also run different tests on each pass, e.g., a different set of URLs, although each run would be a different testing cycle.

To test individual interfaces, for example, you could issue the following command:

Note that in this command, we are testing internet connectivity to the single interface “br0.”

Customise network testing

MAAS allow you to customise network testing according to your needs. You can create your own commissioning scripts and tests related to networking, and you can run them during the network testing portion of the MAAS workflow.

There are no particular restrictions on these scripts, so you can test a wide variety of possible conditions and situations. Administrators can upload network tests and test scripts. Administrators can also create tests which accept an interface parameter, or scripts which apply custom network configurations.

Users can specify unique parameters using the API, override machines which fail network testing (allowing their use), and suppress individual failed network tests. Users can also review the health status from all interface tests, even sorting them by interface name and MAC. In addition, MAAS can report the overall status of all interfaces.