Replace telnetlib with scrapli #279
Conversation
- Add python3-pip, git and scrapli install via pip to all node - Dockerfiles. - Replace all nodes telnetlib functions with new adapated scrapli functions. (wait_write, expect, read_until) - Move Cisco and Juniper nodes to their own vendor subdirectories, fix makefiles to ensure functionality works. - Other things, which should be outlined in the PR.
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It might be worth making another scrapli branch and then I can change this PR to merge into that branch (instead of master). This way other contributors can submit PRs for any changes to other nodes and once all/enough nodes work, that branch can be merged into master? |
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sound idea @kaelemc |
…nfigurations - Startup and bootstrap configurations use scrapli with IOSXEDriver - Changed variable name from 'csr' to 'cat8kv' in cat8kv install function. - Reverted change in bootstrap_spin so that console output is evaluated against empty byte-string instead of regular string.
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IOS-XE nodes (CSR1000V, Cat8kv and Cat9kv) the Scrapli XE driver is now being used. Had some issues with it working with IOS-XE 16.x but it was an error on my end.. got the configs (both bootstrap and startup) to work nicely. |
- existing XRv node uses vmdk image only. This one will use the qcow2 image.
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Maybe this belongs as it's own PR but I've added an xrv_qemu directory. It is the same as XRv but with some modifications to make XRv work when the user provides the qcow2 image. The existing xrv directory requires vmdk images, most users who import images from CML or other places on the web most likely will get a qcow2, this makes it easier for users so they don't have to mess around with I tried one more time to use the scrapli |
- Alter the log levels for some logs from debug->error - Move the VM startup log message and add information about qemu smp and startup RAM.
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Not a trivial change, but I would suggest to create 1 base Dockerfile for all of vrnetlab, and then derive all platform images from that It doesn't make sense to do 100x "install scrapli" in all those separate files - that becomes unmanageable |
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yeah we can definitely create the base image hosted on ghcr.io with base pacakages that every vr system relies on |
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@jbemmel Excellent idea, certainly is/was unmanageable for me |
- This means for all nodes, environment variables are displayed in the logs.
…-XE 16.x compatibility)
- Useful for lower-spec systems where some operations may take time.
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So this is a difficult one to balance, in labs of different sizes the nodes take varying times to boot (depending on system specs etc.).. I'm wondering if we should bump all the scrapli timeouts to something very large to make the connection timing out a non-issue? Currently I have XE devices on 10 minutes, I have a feeling for people with lower-spec systems might hit time-outs meaning they could never boot the device. Should we increase to something very large just to be safe? The base Scrapli |
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I agree, let's have a long enough timeout so that you don't have to guess the time down to minutes. We should leave the timeout configurable via the env var setting that can be then put in the topology file if needed to tune it up |
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Ok 👍, having timeouts as an env var is a good idea |
- New env var SCRAPLI_TIMEOUT added, defaults to 3600 seconds (1 hour). - It's used to enable the user to modify the operation, transport and socket timeout for the Scrapli driver used to apply the config to the CSR.
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I had to remove NETCONF configuration on CSR as different versions of IOS-XE 16.x and 17.x have different behaviors when this command is entered in the config. In 16.x a prompt will appear asking for some confirmation about the NETCONF configuration. I figured it's best to just remove this instead of adding extra complexity to handle the prompt for that single command. Thoughts? |
- Remove env var printing in SROS launch.py (this is done in vrnetlab now) - Comment out clean buffer parameter default (this isn't supported anymore), but just incase we might want to add it back.
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SROS seems to be working fine with minimal changes. I just had to comment out the defaulting of the Also removed the env var printing from the SROS side, This is done as part of vrnetlab now.
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This PR replaces the usage of telnetlib in vrnetlab with scrapli.
Changes
Telnetlib has been removed and replaced and now the Scrapli Base Driver class is used for base telnet functionality.
debian:bookworm-slimfrom the Amazon ECR.gitandpipadded, as well as installation command of Scrapli via the git repo.Cisco and Juniper nodes are in their own vendor-specific subdirectory.
VENDOR_SUBDIRvariable in the Makefiles of each node as well as logic inmakefile.includeso that files get copied one level further (due to vendor subdirectory). IfVENDOR_SUBDIRis1then files are copied one subdirectory level further to account for the vendor subdirectory.Logger for VR class (inherited by all nodes) now uses a logger under the
vrnetlabinstance. This is because Scrapli uses the root logging instance, and outputs all channel output as 'debug' log level.self.loggerwill still write 'debug' logs to stdout (docker logs).Coloured the logging levels so it's easier to see, looks nicer visually too.
Functions
read_until()
telnetlib had a
read_until()function which was used bywait_write. This has been re-implemented under the VR class.Args:
match_str: a string of the text to wait fortimeout: a float of how long to wait before exiting the function even if no match is found. Defaults to None.Returns: All console output that was read up until the match, or function timeout.
wait_write()
Adapted to scrapli, functionality should be analogous to the telnetlib version.
timeout(float): This has been added, and is passed toread_until, Defaults to None.expect()
telnetlib had the
expect()function which was used in thelaunch.pyentrypoint. This new adapted version in the VR class should function the same as the telnetlib one.Args:
regex_list: a list of byte-strings which are used to match via regex on the console output.timeout: a float of how long before the function should just timeout and stop waiting. Defaults to None.Returns: a tuple of:
-1if there was no match. (int)print()
The VR class now has a print function which is used to simply write to stdout and instantly flush. It's used so that the telnet console can output nicely on
docker logs.If the console output was printed via the logger, the formatting would make it difficult to interpret the output.
Args:
bytes: byte-string of what to write to stdout.Usage
Relevant changes to make a node work:
Ensure git, pip and scrapli are installed in the Dockerfile
Replace
self.tn.expect()withself.expect()Use
self.print()to print any console output, do not use logging for this. There is no need todecode()/convert the returned byte-string ofexpect()asself.print()doesn't accept strings, this would result in malformed outputs.Logging levels for any log output should be changed to be more appropriate.
INFO is Green
WARNING is Yellow
ERROR/DEBUG is Red
Other
Only Cisco nodes have been tested working (csr1000v, cat8kv, cat9kv, ASAv, FTDv, vIOS, n9kv, XRv, XRv9k). I have not tested nxos.
I don't expect other nodes to 'plug and play' and work perfectly from the get go, I'm sure I have made errors or overlooked something so some work is required on the other nodes to ensure functionality.
Collaboration from others is required so we can confirm all nodes work reliably (as well as to fix some other possible issues in the way i've implemented the changes). I'm open to feedback 😊.