7 ms·

One of my favorite patterns for updating configuration in-band I learned from Juniper routers. When you enact a new configuration you can have it automatically

One of my favorite patterns for updating configuration in-band I learned from Juniper routers. When you enact a new configuration you can have it automatically rollack after some period of time unless you confirm the configuration. Often the pattern is to intentionally have it roll back after a short period (e.g. one minute), then again after a longer period, (e.g. 10 minutes) and the on the last time you make it permanent. I feel like all configuration systems should allow for a similar mechansim

mikro2nd 7y ago
I recall one occasion when I thanked all the gods for having been taught this pattern... firewall changes made from 2000km away that went pear-shaped...
xtracto 7y ago
This has been in Windows in the screen resolution configuration option for some time.
- stingraycharles 7y ago
  I think it has been like this since Windows 3.1, so “some time” might be an understatement.
- jonplackett 7y ago
  Ah, the lost joy of trying out various screen resolutions and refresh rates on your new monitor.
  - novaleaf 7y ago
    nvidia drivers (probably ati too) let you create custom resolutions. I got my monitor to do 1080p@120hz that way. (default supported is only 60hz)
    - MagicPropmaker 7y ago
      Yeah, but this is largely moot now that monitors have "native resolutions" with fixed numbers of pixels.
fragmede 7y ago
This is called a watchdog timer, and is frequently used in embedded systems where "bare-metal" "OS" upgrades need to occur. You think it's stressful upgrading a router on the other side of the planet, try upgrading the firmware on the Mars Rover! (I've only heard stories.)
- gregschlom 7y ago
  That's not really what a whatchdog timer is though. https://en.m.wikipedia.org/wiki/Watchdog_timer https://en.m.wikipedia.org/wiki/Watchdog_timer
  - penagwin 7y ago
    While Watchdog Timer is more so an external-to-the-cpu system for embedded systems, I'm not sure if there's a word for it in the software world other then some form of timeout?
    - tntn 7y ago
      A watchdog timer is so named because it watches for some undesirable condition (usually a hang) and takes action if the condition lasts too long. This sort of auto-rollback is not that because it doesn't detect if something is bad, just rolls it back unless you tell it not to.
      - penagwin 7y ago
        Actually I think a watchdog timer doesn't watch anything except it's timer. > A watchdog timer is an electronic timer that is used to detect and recover from computer malfunctions. During normal operation, the computer regularly resets the watchdog timer to prevent it from elapsing, or "timing out". It doesn't care about the state of anything except it's timer, and the only way to prevent it from activating is to reset the timer or disable the watchdog altogether. That would still make sense in terms of auto-roll backs. You can't trust the state as a miss-configuration makes it unreliable. The only difference I see from "auto-rollbacks" and "watchdog timers" is that watchdog timers are usually meant to be permanent, while auto-rollbacks are temporary (once you confirm it the auto-rollback never occurs again).
mikevin 7y ago
Networking hardware often has this option and I miss it often when deploying configuration changes to software. Its something a lot more systems could use.
rossjudson 7y ago
"Do you want to keep this resolution?" Yes|No

mikro2nd 7y ago

I recall one occasion when I thanked all the gods for having been taught this pattern... firewall changes made from 2000km away that went pear-shaped...

xtracto 7y ago

This has been in Windows in the screen resolution configuration option for some time.

stingraycharles 7y ago
I think it has been like this since Windows 3.1, so “some time” might be an understatement.
jonplackett 7y ago
Ah, the lost joy of trying out various screen resolutions and refresh rates on your new monitor.
- novaleaf 7y ago
  nvidia drivers (probably ati too) let you create custom resolutions. I got my monitor to do 1080p@120hz that way. (default supported is only 60hz)
  - MagicPropmaker 7y ago
    Yeah, but this is largely moot now that monitors have "native resolutions" with fixed numbers of pixels.

fragmede 7y ago

This is called a watchdog timer, and is frequently used in embedded systems where "bare-metal" "OS" upgrades need to occur. You think it's stressful upgrading a router on the other side of the planet, try upgrading the firmware on the Mars Rover! (I've only heard stories.)

gregschlom 7y ago
That's not really what a whatchdog timer is though. https://en.m.wikipedia.org/wiki/Watchdog_timer https://en.m.wikipedia.org/wiki/Watchdog_timer
- penagwin 7y ago
  While Watchdog Timer is more so an external-to-the-cpu system for embedded systems, I'm not sure if there's a word for it in the software world other then some form of timeout?
  - tntn 7y ago
    A watchdog timer is so named because it watches for some undesirable condition (usually a hang) and takes action if the condition lasts too long. This sort of auto-rollback is not that because it doesn't detect if something is bad, just rolls it back unless you tell it not to.
    - penagwin 7y ago
      Actually I think a watchdog timer doesn't watch anything except it's timer. > A watchdog timer is an electronic timer that is used to detect and recover from computer malfunctions. During normal operation, the computer regularly resets the watchdog timer to prevent it from elapsing, or "timing out". It doesn't care about the state of anything except it's timer, and the only way to prevent it from activating is to reset the timer or disable the watchdog altogether. That would still make sense in terms of auto-roll backs. You can't trust the state as a miss-configuration makes it unreliable. The only difference I see from "auto-rollbacks" and "watchdog timers" is that watchdog timers are usually meant to be permanent, while auto-rollbacks are temporary (once you confirm it the auto-rollback never occurs again).

mikevin 7y ago

Networking hardware often has this option and I miss it often when deploying configuration changes to software. Its something a lot more systems could use.

rossjudson 7y ago

"Do you want to keep this resolution?" Yes|No