gvalkov

Joined 14 years ago

Karma

226

Submissions

Member since

May 8

View on Hacker News

Recent submissions

Comment · 5 months ago

The squeeze is real even at the SME level. We recently wanted to add another TB of memory to several servers (we do EDA chip design, which eats a lot of memory). Quotes came back to about €200k for 48 x 96GB DDR5-5600 RDIMMs. Mind you, this is for refurbished memory with 1 year warranty. I'm still figuring out if this is FU-pricing or just how things are going to be from now on.

Spec-ing and buying servers has become quite the pain in the past year, at least at the relatively-small scale we operate at. It's "dynamic pricing" with most quotes being valid for 24 hours :(

Comment · 7 months ago

In zsh you can bind "push-line-or-edit". In bash and all readline programs, you can approximate it with C-u followed by C-y (i.e. cut and paste). My history is still full of '#' and ':' (csh trauma) prefixed command-lines like you described though ...

Comment · 1 year ago

I'm using that case with with a 200mm fan front-panel mod[1]. Despite its size, it gets pretty cramped. It's just hard to keep it organized without a dedicated SATA backplane.

[1]: https://www.printables.com/model/866109-200mm-fan-front-for-...

Comment · 1 year ago

In Python 3.8 - https://peps.python.org/pep-0572/

Comment · 1 year ago

This is nitpicking, but this is a good usecase for the := operator:

  if not (API_KEY := os.getenv("API_KEY")):
      ...

For internal tools I just let os.environ["API_KEY"] raise a KeyError. It's descriptive enough.

Comment · 1 year ago

We're still serving a cgi-bin directory at work for the occasional quick and dirty internal web app. The ergonomics are great as long as you keep it simple. The fact that it's cgi doesn't mean you have to print http/1.0 to stdout manually. For example, in python the builtin wsgiref.handlers.CGIHandler lets you run any wsgi app as a cgi script:

  import wsgiref.handlers, flask
  app = flask.Flask(__name__)
  wsgiref.handlers.CGIHandler().run(app)

The way we run the scripts is with uwsgi and its cgi plugin[1]. I find it simpler and more flexible than running apache or lighttpd just for mod_cgi. Since uwsgi runs as a systemd unit, we also have all of systemd's hardening and sandboxing capabilities at our disposal. Something very convenient in uwsgi's cgi handling that's missing from mod_cgi, is the ability to set the interpreter for a given file type:

  cgi = /cgi-bin=/webapps/cgi-bin/src
  cgi-allowed-ext = .py
  cgi-helper = .py=/webapps/cgi-bin/venv/bin/python3  # all dependencies go here

Time to first byte is 250-350ms, which is acceptable for our use case.

[1]: https://uwsgi-docs.readthedocs.io/en/latest/CGI.html

Comment · 1 year ago

I recently built something[1] similar, though with far less effort and sophistication than the author. The goal was to have a plug-and-play audiobook player for an elderly family member with impaired vision. In retrospect, it would have been better to adapt an old phone or tablet with a macropad rather than build this on top of an espmuse speaker[2].

I keep thinking that a cassette player would be the ideal interface for something like this. The controls are as obvious and as tactile as it gets and the whole analog-mechanical experience is familiar to folks from that generation. If only tapes could hold more than two hours of audio ...

[1]: https://www.printables.com/model/1269288-audiobook-player

[2]: https://raspiaudio.com/product/esp-muse-luxe/

Comment · 3 years ago

Python 3.11 also claims [1] to be 10-60% faster than 3.10, which is the version that the benchmarks game is using at this time. The difference in used RSS is also quite interesting in this comparison.

  [1]: https://docs.python.org/3/whatsnew/3.11.html#whatsnew311-faster-cpython

Comment · 4 years ago

A hidden gem of pyenv is its 'python-build' plugin, which just lets you build and install any Python version in the least number of steps:

  git clone https://github.com/pyenv/pyenv.git
  cd pyenv/plugins/python-build/bin
  ./python-build --definitions
  ./python-build 3.10.8 /opt/python/3.10.8
  PYTHON_CONFIGURE_OPTS="--enable-shared" ./python-build 3.10.8 /opt/python/3.10.8

Comment · 4 years ago

One nice use of dd is to append an ssh key to .authorized_keys on a host that doesn't allow shell or sftp access (which is what ssh-copy-id needs):

  cat id_rsa.pub | ssh $host 'dd of=.ssh/authorized_keys oflag=append conv=notrunc'

Comment · 5 years ago

It's great to see how far Podman (and its sister projects) have come. I think it's a reliable tool and I'm a happy user both personally and professionally.

We make heavy use of Podman in our infrastructure and it's mostly a pleasure. My current pet peeves are that:

1) Ansible's podman_container module is not as polished as docker_container. I regularly run into idempotency issues with it (so lots of needlessly restarted containers).

2) Gitlab's Docker executor doesn't support Podman and all our CI agents run on CentOS 8. I ended up writing a custom executor for it and it's working quite well though (we're probably not going back to the container executor even if it supported Podman, since the custom executor offers so much more flexibility).

3) GPU support is easier/more documented on Docker. For this reason, the GPU servers we have are all Ubuntu 20.04 + Docker since it's the more beaten path.

4) Podman-compose just needs more work. Luckily for us, it seems that Podman 3.x will support docker-compose natively [1].

As mentioned, our CI environment is very dependent on Podman. The first step of every Gitlab pipelines is to build the container image in which the rest of the jobs will run. I find that it's simpler to have a shell executor in a unprivileged, restricted environment (i.e. can only run `podman build`) than setting up dind just for building images. All jobs that follow are ran in rootless containers, for that nice added layer of security.

Wishing all the best to the Podman, Buildah and Skopeo teams.

[1]: https://www.redhat.com/sysadmin/podman-docker-compose

Comment · 5 years ago

Quite a lot is possible with CNI [1]. For example, we use this setup to give real IPs to containers:

  # /etc/cni/net.d/testnet.conflist
  {
    "cniVersion": "0.4.0",
    "name": "testnet",
    "plugins": [
      {
        "type": "bridge",
        "bridge": "br0",  # main host interface is part of this bridge
        "ipam": {
          "type": "host-local",
          "subnet": "10.0.0.0/16",
          "gateway": "10.0.0.1",
          "routes": [{ "dst": "0.0.0.0/0"}]
        }
      }
    ]
  }

You can then start a container and operate on its network namespace for added flexibility:

  podman run -it --net testnet --ip 10.0.0.2 ...

  ns=$(basename $(podman inspect $id | jq -r '.[0] .NetworkSettings .SandboxKey'))
  ip netns exec $ns ip route add ...

[1]: https://github.com/containernetworking/cni

Comment · 7 years ago

A device that waits for the SSID of my Olympus WiFi-enabled camera to show up and then sync all new photos:

https://github.com/gvalkov/olympus-photosync-server https://github.com/gvalkov/olympus-photosync

Comment · 7 years ago

It's not possible in the way it's possible in SCons. You can basically use custom_target, but its usefulness is limited since there are no user-defined functions in Meson's subset of Python. CMake is a little better in this regard here, since it at least offers macros and functions.