4 ms·

I'm not sure why systemD is needed for restarting a process what about a simple loop with an if statement? Process isolation to run a go binary on a presumably

by soheil 6y ago

I'm not sure why systemD is needed for restarting a process what about a simple loop with an if statement? Process isolation to run a go binary on a presumably dedicated web server? Privileged sockets, not even sure what those might be. The point of this post is to not complicate things, but what I hear is even more complicated be it via a docker alternative.

bostonsre 6y ago
Systemd config files are fairly simple and straightforward. It gives a simple interface to start/stop/restart processes and lets you do things like automatically start a process on server boot.
- CameronNemo 6y ago
  systemd unit files are cleaner than some init scripts, but they only have one implementation, which works on one libc and one kernel. uf.
  - yjftsjthsd-h 6y ago
    > only have one implementation, which works on one libc and one kernel I agree overall, but apparently systemd supports musl. No clue why or who uses it, but it's a thing.
    - CameronNemo 6y ago
      Not according to several people who maintain patches outside of systemd explicitly for musl compatibility. Did this change recently? Last I heard, systemd maintainers explicitly rejected attempts to support alternate libc implementations.
viraptor 6y ago
> I'm not sure why systemD is needed for restarting a process what about a simple loop with an if statement? It's not needed, but that's why a lot of older apps have their very custom solution to deal with that issue. (For example MySQL) Each with their custom exit condition handling, cleanup, backoff, etc. A simple loop also won't cleanup processes forked from the main server. This 1kLoC script https://github.com/mysql/mysql-server/blob/8.0/scripts/mysqld_safe.sh https://github.com/mysql/mysql-server/blob/8.0/scripts/mysql... can be almost entirely replaced with a few lines of systemd.service config. (with fairly logical names for each setting) Now we can replace those with "Restart=always". If you want to be fancy, you could even add a watchdog. > Process isolation to run a go binary on a presumably dedicated web server? 1. "presumably" 2. Apparently a web server which gets SSH sessions from devs - nice place to check for forwarded keys or collect passwords. > Privileged sockets, not even sure what those might be. Ports below 1024 (or whatever your local threshold is) > but what I hear is even more complicated It really isn't. Just unfamiliar to you.
- jfoutz 6y ago
  if you go down the Restart=always route, please take a long look at StartLimitIntervalSec, RestartSec, StartLimitBurst. in some failure modes always isn't quite always always.
- soheil 6y ago
  Yeah it really is complicated, probably just very familiar to you. I Google systemD the first result has 160 sections just in the documentation table of contents alone [0]. [0] https://www.freedesktop.org/wiki/Software/systemd/ https://www.freedesktop.org/wiki/Software/systemd/
  - viraptor 6y ago
    The linked page is not a documentation ToC. Why would you claim that? For day to day usage there are two man pages which should be enough for reference: https://www.freedesktop.org/software/systemd/man/systemd.exec.html https://www.freedesktop.org/software/systemd/man/systemd.exe... and https://www.freedesktop.org/software/systemd/man/systemd.service.html https://www.freedesktop.org/software/systemd/man/systemd.ser... Or you could start with one of the blog posts linked in the page you referenced.
    - SSLy 6y ago
      By his peculiar capitalization you can tell he's a hater that still hasn't come to terms with it, 10 years later.
      - soheil 6y ago
        Using camel case means I'm a hater?
      - CameronNemo 6y ago
        Or is tired of systemd being auto corrected to systems.
    - soheil 6y ago
gary_0 6y ago
> I'm not sure why systemD is needed for restarting a process You need a systemd unit file that starts your daemon properly when the server boots anyways (most common distros use systemd for init), and it's only a few more lines to make sure it gets restarted if it dies.

by soheil 6y ago

bostonsre 6y ago

Systemd config files are fairly simple and straightforward. It gives a simple interface to start/stop/restart processes and lets you do things like automatically start a process on server boot.

CameronNemo 6y ago
systemd unit files are cleaner than some init scripts, but they only have one implementation, which works on one libc and one kernel. uf.
- yjftsjthsd-h 6y ago
  > only have one implementation, which works on one libc and one kernel I agree overall, but apparently systemd supports musl. No clue why or who uses it, but it's a thing.
  - CameronNemo 6y ago
    Not according to several people who maintain patches outside of systemd explicitly for musl compatibility. Did this change recently? Last I heard, systemd maintainers explicitly rejected attempts to support alternate libc implementations.

viraptor 6y ago

> I'm not sure why systemD is needed for restarting a process what about a simple loop with an if statement? It's not needed, but that's why a lot of older apps have their very custom solution to deal with that issue. (For example MySQL) Each with their custom exit condition handling, cleanup, backoff, etc. A simple loop also won't cleanup processes forked from the main server. This 1kLoC script https://github.com/mysql/mysql-server/blob/8.0/scripts/mysqld_safe.sh https://github.com/mysql/mysql-server/blob/8.0/scripts/mysql... can be almost entirely replaced with a few lines of systemd.service config. (with fairly logical names for each setting) Now we can replace those with "Restart=always". If you want to be fancy, you could even add a watchdog. > Process isolation to run a go binary on a presumably dedicated web server? 1. "presumably" 2. Apparently a web server which gets SSH sessions from devs - nice place to check for forwarded keys or collect passwords. > Privileged sockets, not even sure what those might be. Ports below 1024 (or whatever your local threshold is) > but what I hear is even more complicated It really isn't. Just unfamiliar to you.

jfoutz 6y ago
if you go down the Restart=always route, please take a long look at StartLimitIntervalSec, RestartSec, StartLimitBurst. in some failure modes always isn't quite always always.
soheil 6y ago
Yeah it really is complicated, probably just very familiar to you. I Google systemD the first result has 160 sections just in the documentation table of contents alone [0]. [0] https://www.freedesktop.org/wiki/Software/systemd/ https://www.freedesktop.org/wiki/Software/systemd/
- viraptor 6y ago
  The linked page is not a documentation ToC. Why would you claim that? For day to day usage there are two man pages which should be enough for reference: https://www.freedesktop.org/software/systemd/man/systemd.exec.html https://www.freedesktop.org/software/systemd/man/systemd.exe... and https://www.freedesktop.org/software/systemd/man/systemd.service.html https://www.freedesktop.org/software/systemd/man/systemd.ser... Or you could start with one of the blog posts linked in the page you referenced.
  - SSLy 6y ago
    By his peculiar capitalization you can tell he's a hater that still hasn't come to terms with it, 10 years later.
    - soheil 6y ago
      Using camel case means I'm a hater?
    - CameronNemo 6y ago
      Or is tired of systemd being auto corrected to systems.
  - soheil 6y ago

gary_0 6y ago

> I'm not sure why systemD is needed for restarting a process You need a systemd unit file that starts your daemon properly when the server boots anyways (most common distros use systemd for init), and it's only a few more lines to make sure it gets restarted if it dies.