On Fri, Jul 29, 2022 at 10:55:45AM +0000, Juraj Linkeš wrote:
<snip>
> + self.session = pxssh.pxssh(encoding="utf-8")
> + self.session.login(
> + self.node,
> + self.username,
> + self.password,
> + original_prompt="[$#>]",
> + password_regex=r"(?i)(?:password:)|(?:passphrase for key)|(?i)(password for .+:)",
> + )
> + self.logger.info(f"Connection to {self.node} succeeded")
> + self.send_expect("stty -echo", "#")
> + self.send_expect("stty columns 1000", "#")
First of all, thanks for those changes! Having DTS inside DPDK makes
test synchronization a lot easier. I'm happy to say (unsurprisingly)
that it works with my RISC-V HiFive Unmatched board like a charm.
Though there is a small issue with the lines above. They assume "#" as
the prompt sign, even though original_prompt was set to "[$#>]". This
touches on two problems:
1. # is usually a root prompt - is DTS assumed to be run with root
privileges? DPDK may (in theory) run without them with some permission
adjustment (hugetlb, VFIO container, etc.). If we assume DTS needs
root access, this has to be both documented and validated before
running the whole suite. Otherwise it'll be hard to debug.
Around a year ago there were some attempts to get DTS to not require root. This ended up running into issues because DTS sets up drivers for you, which requires root as far as I know, as well as setting up hugepages, which I think also
requires root. The current version of DTS can probably run without root, but it will probably stop working as soon as DTS starts interacting with PCI devices. Elevating privileges using pkexec or sudo is less portable and would require supporting a lot more
forms of authentication (kerberos/ldap for enterprise deployments, passwords, 2fa, etc). It is much easier to say that the default SSH agent must provide root access to the SUT and Traffic Generator either with a password or pre-configured passwordless authentication
(ssh keys, kerberos, etc).
[Honnappa] One of the feedback we collected asks to deprecate the use of clear text passwords in config files and root user. It suggests to use keys and sudo. It is a ‘Must Have’ item.
I agree it should be documented. I honestly didn't consider that anyone would try running DTS as a non-root user.
[Honnappa] +1 for supporting root users for now and documenting.
2. Different shells use different prompts on different distros. Hence
perhaps there should be a regex here (same as with original_prompt)
and there could be a conf.yaml option to modify it on a per-host
basis?
As far as customizing the prompts, I think that is doable via a configuration option.
As far as different shells, I don't think we were planning to support anything besides either bash or posix-compatible shells. At the moment all of the community lab systems use bash, and for ease of test development it will be easier to mandate that everyone
uses one shell. Otherwise DTS CI will need to run once for each shell to catch issues, which in my opinion are resources better spent on more in-depth testing of DTS and DPDK.
[Honnappa] +1 for using just bash, we can document this as well.