FYI VSCode's SSH Agent is a godsend for remote development - the "disadvantages" that Fly lists are part of its advantages. I've worked in several teams that have made extensive use of the extension, and it's never been an issue. You can restrict SSH access arbitrarily to ensure whatever security or access guardrails you need.
It would be one thing if the plugin was just a wrapper and people were still expected to know ssh but the plugin abstracts away all that and is intended to make it a "use VSCode on remote machine" tool. So it needs to do more than just handle creds, otherwise it creates a divergent experience while making people think it's just ssh
Also, timeouts...
Also, does anyone know if VSCode supports mosh?
if [[ $TERM_PROGRAM = vscode && -f /etc/motd ]]; then
cat /etc/motd
fi
$ echo $TERM
xterm-256color
$ echo $TERM_PROGRAM
vscode >>> Assuming your users use the integrated terminal regularly
cat /etc/motd >&2
But so is the question. MOSH interprets all the escape sequences and uses them to decide what to send to the client. That way if you tail a log file and then get disconnected, you don’t have to download every line of text that was output to your terminal while you were away; it can just send you what is currently visible.
MOSH is strictly for interactive use; never ever for automated uses like TRAMP or VSCode or sshfs.
Of course, it is a pity Microsoft doesn't open source it. But there are some well-maintained open source alternatives, e.g. https://github.com/jeanp413/open-remote-ssh and https://github.com/F1yingWhite/fast-remote-ssh (I haven't got around to giving either of them a go–but I really should.)
It also (AIUI) tries to walk the entire file tree, so have fun with NFS (auto)mounts.
It also amounts to letting off fork bombs: we set up limits for a maximum of 256 process per UID, and regularly get folks asking "what does this 'cannot fork' message mean?": it mean you're trying to DoS the system.
The max limit on 64 bit systems is what, 4,194,303? So if you have over 16,000 users per VM this limit makes sense, otherwise it just seems user-hostile.
Yes, under Linux (and most unix-a-like systems) small processes are cheap to bring up and tear down which is why we create them so much, and it is not uncommon for complex interactive commands and bits of shell scripts to create several¹, but these are all likely to be short-lived so a limit of 256 certainly doesn't seem to be obscenely low to me.
What could it be doing that requires 256+ processes to be kept around for a prolonged time?
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[1] made up example: comparing filtered content of two gzipped files and sending the result through a script to send alerts by mail if certain things are found would be 7+ (2x gzip, 2x or more grep, diff, bash, mail or curl depending on what service you are sending alerts through)
And yet we still regularly loads of >100 on our 64 core HPC login codes, and swap is regularly used even with 96G of system memory (we have per UID memory limits too).
What's hostile is the VSCode (and Codex and Claude) makers developing tools that basically DoS a system because they assume it will operate only on single-user machines.
(And WTF are you doing that you're forking 256 processes? We have quite a few expensive HPC nodes: use those to build, not the damn login nodes.)
> The max limit on 64 bit systems is what, 4,194,303?
if you have a paid tier which offers more, you do you
if this is internally and you are a service provider to people.. why?
also 256 is not much today, my mac with a few things open is at 800
Compared to someone on an ssh connection. No desktop, no Apple Account, no user session programs, etc. You really don’t need much
i do not know why/in which context you are running this, and how frequently your users are executing forkbombs(i assume school/kids?)
my server is also running 400 something processes, one postgres instance alone is like 40?
(Also this isn't a default limit.)
> they are too low for modern development...
Too low? 256 reads as *pretty* generous to me.
The users can develop on >100 compute nodes, but choose not to bother doing any kind of forwarding/proxying/jumping to them and just do stuff on the login nodes.
If they can't be bothered to do a "ssh -J …" then it's on them. The resources are there.
> what do people put there?
\033[1;31mCLEAN YOUR FUCKING DRIVE OR I'LL DO IT FOR YOU!\033[0m
Quotas mean "more than this is clearly too much" not "please use this space".
In good times nobody minds, but in bad times when you just can't extend the drive you have to tell people off. Part of the job of making sure the system can continue to work for what you need it, under _real_ constraints.
You may have to delete stuff, you may have to shut the server down to save power. You may have to limit clock speeds. It depends on the environment and "it really should work because it should be covered by next day on site warranty and you could download more ram" often doesn't apply.
super tangential, but makes me think I never realised that "quota" can either be a lower or an upper bound depending on context
Apps had a (recommended and then user-configurable) "Minimum memory" and "Preferred memory." The app would not launch if the OS couldn't give it the minimum. It would then give the app up to the preferred amount, if available, exclusively... This was in the era before virtual memory and paging, so there was no easy way to share memory across an application boundary.
This mean that savvy users with high-resource tasks knew you had to launch your apps in a certain order to get the architecture into the configuration to do their work.
Ah, memories of Uni, back when storage was fairly expensive, where we had both hard and soft quotas. The soft quota would allow for temporary growth of build artefacts and things¹ but you would get stern emails if you were over your soft quota for 24 hours, and if you persisted without good reason³ your hard quota would be reduced so you effectively have no soft quota any more.
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[1] some machines had no local storage that the user could touch so putting them there was not always possible, some people on Windows machines had local storage but didn't have the relevant tools locally so were actually running things on the shared server(s)² instead of that just being a storage resource
[2] via telnet/rsh/rlogin: yes, I am that old… SSH was a thing by that point, though OpenSSH wasn't, and I was using it where available, but the use of older plain-text protocols was still far far more common
[3] it wasn't actually difficult to justify a quota extension for project work, in fact people enrolled on certain modules got higher quotas automatically
Don't worry, disk got expensive again. Disks are usually at least 2X more expensive than a year ago currently. Sometimes 3X more.
HDD prices are a bit more reasonable. Mostly because they are so heavy. Still insane to where prices were just 12 months ago
Probably why both soft and hard limits were developed.
In my ecosystem, developers don't have time to glad-hand like this; if there are issues with DEV_NODE_CFG_1_29875, we might talk about it over Slack (because I'm the first one to know there's a problem as the end-user), and if we can't sort it out they'll give me some time to backup, blank the whole machine, and I get a brand-new image of DEV_NODE_CFG_1_29875.
I can't even tell you off the top of my head what territory the physical machine is running in or whether it's the only dev-node on that hardware.
(Broadly speaking, I think Microsoft is assuming cattle ecosystems; they're not openly-hostile to pets per se, but they have a strict ranking of the priorities because the "cattle ranches," as it were, bring in more money).
> but that's probably not a universal stance.
Another frequent problem we had was people using the systems while others were. They wouldn't check the machine's status. And of course you can guess that I wasn't allowed to add a scheduler.
A lot of groups do things in janky ways. Often not because they don't know any better but because leadership doesn't and is assertive
It sounds like a lot, but it's fairly compact and really helps when you need to absolutely sure where you are and you have eight terminal windows open.
There will be a system outage 2026-11-11 (08:00 ET) to 2026-11-13, Wed to Fri.
"I have not touched any machines in fra3 for a week, how the hell would I know of it? Why do we even have #fra3-maintenance and #maintenance channels then, if that's your stance?"
We put the MOTD up ≥7 days in advance and put it in relevant Slack channels.
We still get "Is Foo down?" the day of.
Like, I used to, but it was in the early 1990s.. People look at them now?
Next I'll be asking people to finger me to get my availability ..
Can still do it these days of course, but one with a seriously copious helping of ssh in the mix too ..
Trouble is, nobody else can do it. The only reason I have to use {social-media-blob} is because my friends don't know how to finger.
We've had the same issue with our local HPC; a few login nodes serving hundreds of users at a time, and each login node used to get swamped by these dangling SSH sessions/servers. They also wrote a script that shuts down all sessions once a day to save the login nodes.
No snark: does your org also regularly check the mail spool and expect individual users to do so as well?
But then again, I had people who would run jobs without checking if the machine is already in use. Obviously these people didn't check email or slack either...
https://github.com/jeanp413/open-remote-ssh
I run the editor (and its extensions), my projects and any agent harnesses from inside a container and use that extension to get an editor.
This is mostly to protect my credentials and data from malicious extensions/dependencies/rogue-agents, bu it also lets me quickly port my dev environment to any machine (I use linux at home and macos at work). Just install podman, install VSCodium, add the SSH extension, build image, add my utility shellscripts (to quickly get in and out of the container in a shell) and done.
Apparently Microsoft keep some VSCode APIs proprietary so only its own extensions can use it (allegedly for security reasons), which is why this specific extension only works in VSCodium. I wonder if it is vulnerable to the same things the article points out.
Happy Ungoogled Chromium user though
So how to make the plugins remote-capable? You could write a massive virtualization layer that captures all system calls and forwards them to the remote - or, you could run the plugin on the remote and just pass the user commands and UI updates over the connection.
VSCode does the latter, so the nodejs runtime is where all the plugins are running on the remote.
(I understood the reason, I didn't say it was a good reason...)
Also, I realized that students are likely to use vscode to connect to embedded Linux machines and fill up their emmcs (and RAM), so I came up with a partial solution for our experiment's yocto image (https://github.com/RNO-G/meta-rno-g/blob/main/recipes-suppor...) , but a more general solution would be nice. Probably better to just not allow any node process to run via LSM.
At least when Python minimum version changed there was a separate extension forked from the original that I can use when I need to work on old code alongside the new extension for more modern code bases. Sadly, no such thing exists for remote editing that I know of.
The problem is the remote host has control over local host through the protocol.
It turns out ssh is, well, a little awful. I use emacs as my primary dev tool, and I hardly ever tramp to a remote machine, preferring instead to ssh via terminal to the machine and run a local emacs instance on the target machine. Reason being that the ssh connection underlying Tramp can get downright creative in the ways it crashes or hangs emacs.
SSH, as a protocol, dates back to a time where you even though the network was built to be (ostensibly) robust against attack, there's a deeply-ingrained assumption that it's mostly up and persistent. That assumption doesn't work well in the era of laptops and wifi, as anyone who uses emacs regularly may be able to tell you. The defaults for SSH are wrong for the modern world, and once you tweak those the protocol reliability (against dropped or rerouted connection, not data corruption) is still rough.
Using SSH as a springboard to inject a better-designed protocol server is the right solution.
It's good that the system can be tuned to work better, but the tricky bit is that the vscode solution just doesn't require that; for most people (it seems), It Just Works.
I'm not surprised people trying to provide remote code editing to non-trusted clients are freaked out by it, but it is a great tool when operating in a trusted circle.
How, specifically for VSCode?
It always felt to me more like a desperate attempt by Microsoft to regain the IDE market share as low end FOSS editors started taking over. So MS wanted to appeal to the open source community.
And it worked. Even if the primary build of VSCode which most people run isn’t technically open source.
The FOSS text editor space was always crowded between vim and emacs. FOSS alternatives would get measured against these 2 behemoths and it was a tall order to compete against. Now FOSS IDEs were a different story.
Java, C#, and C++ had many sophisticated and advanced IDEs, some FOSS some not. However, PHP, Python, Ruby, and JavaScript were quickly gaining huge mindshare and those developers didn’t want to install Visual Studio, Eclipse, NetBeans, or IntelliJ. It’s a tough proposition to tell a Ruby dev to install Java, then install Eclipse, then install an extension, then learn Eclipse nonesense just to edit your Ruby files vs “just open SublimeText and edit your files”. Most of what those developers wanted was just syntax highlighting and basic directory navigation to begin with. Atom/vscode were an attempt at SublimeText alternative. VScode was objectively better than Atom and TypeScript was also objectively better than CoffeeScript.
The FOSS languages were taking over and there was less reliance on the traditional IDEs that MS (amongst others) were building.
MS wanted to appear more FOSS friendly so released VSCode.
Sorry for the misunderstanding that caused. Though the upside was it did lead to your excellent comment adding the detail it did.
Edit: there's a security note (still) on the remote ssh extension page:
Security Note Using Remote-SSH opens a connection between your local machine and the remote. Only use Remote-SSH to connect to secure remote machines that you trust and that are owned by a party whom you trust. A compromised remote could use the VS Code Remote connection to execute code on your local machine.
https://marketplace.visualstudio.com/items?itemName=ms-vscod...
seize the control plane.
The ability to remotely run arbitrary code on a machine that intentionally gives SSH shell and write+execute access to the filesystem is not a vulnerability just because it's a productivity aid to users who want to leverage this access to do bad things on the remote machine.
A remote access protocol that gives a potentially untrustworthy remote system the ability to execute arbitrary code on the local machine is a serious problem in any scenario where the remote connection is presumed to be a one-way trust boundary.
Which of course includes any scenario where I myself deliberately run untrustworthy code on the remote, no matter how much I trust the remote itself and its owners.
Otherwise, you could see Javascript running on a server and instantly know something was odd, depending on the server.
[1] - https://www.darktrace.com/blog/darktrace-identifies-campaign...