Re: Linux: concerns over systemd [OT]
On 10/22/2014 23:02, Jim Mercer wrote:
if reducing boot time from 20 minutes down to 1 minute, in a server environment, is a serious issue for you, maybe you should be looking at why you need to reboot so often?
That is the question I have been asking myself. Back in the day we took it a a failure if a reboot happened. (I remember discussions about needing to reboot to keep counters from overflowing. I thought programming for counter wrap was a better idea.) -- The unique Characteristics of System Administrators: The fact that they are infallible; and, The fact that they learn from their mistakes. Quis custodiet ipsos custodes
On Wed, 22 Oct 2014, Larry Sheldon wrote:
That is the question I have been asking myself.
Back in the day we took it a a failure if a reboot happened. (I remember discussions about needing to reboot to keep counters from overflowing. I thought programming for counter wrap was a better idea.)
When I see a machine with a long uptime I ask myself: 1. When was the last kernel update? 2. Do we know it would come back cleanly when it is rebooted? 3. What would happen to the site if that machine went offline? -- Simon Lyall | Very Busy | Web: http://www.simonlyall.com/ "To stay awake all night adds a day to your life" - Stilgar
Ok. As a highly on- list-topic example of why distrust is called for... Without referring to the systemd source code*, does anyone know what systemd uses to select between networking subsystems (i.e. NetworkManager, the new standard as of RHEL 7, vs /etc/ sysconfig/network-scripts/, etc.). NetworkManager is default but disableable and it magically falls back to network-scripts dir, but the fallback is nearly undocumented and the selection behavior appears completely undocumented. If by some chance you do know this, where did you come by that knowledge? Hopefully with URLs. (* don't bother telling me to read the source. I'm reading...) If I cannot find credible documentation of this, as networking person as well as enterprise sysadmin, this is a Problem.) George William Herbert Sent from my iPhone
On Thu, Oct 23, 2014 at 12:28 AM, George Herbert <george.herbert@gmail.com> wrote:
Ok. As a highly on- list-topic example of why distrust is called for...
Without referring to the systemd source code*, does anyone know what systemd uses to select between networking subsystems (i.e. NetworkManager, the new standard as of RHEL 7, vs /etc/ sysconfig/network-scripts/, etc.). NetworkManager is default but disableable and it magically falls back to network-scripts dir, but the fallback is nearly undocumented and the selection behavior appears completely undocumented.
systemctl status NetworkManager.service systemctl status network.service I don't think that there's anything magic about it, you have one or the other enabled. Adding NM_CONTROLLED=yes/no to /etc/sysconfig/network-scripts/ifcfg-* gives you per-interface control over whether NetworkManager or the network scripts are used for managing the interface. If neither is enabled you probably end up with no networking.
If by some chance you do know this, where did you come by that knowledge? Hopefully with URLs.
I have access to systems that run systemd and I tried a couple of things... Also, I've been managing Red Hat systems for a long time and have known about this for a while. But a little bit of googling and I found this: https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/htm... Unless you're running systemd-networkd, this is really distro-specific stuff as I expect that most distros will want to preserve some backward compatibility with "legacy" network configuration. -- Jeff Ollie
On 10/22/14 9:29 PM, Larry Sheldon wrote:
On 10/22/2014 23:02, Jim Mercer wrote:
if reducing boot time from 20 minutes down to 1 minute, in a server environment, is a serious issue for you, maybe you should be looking at why you need to reboot so often?
That is the question I have been asking myself.
Back in the day we took it a a failure if a reboot happened. (I remember discussions about needing to reboot to keep counters from overflowing. I thought programming for counter wrap was a better idea.)
Back over here in router-land when the cat65k vss pair went down it's at least 20 minutes before it's back. If you enjoy what may be the longest minutes of your life try tripping over a bug that takes out two pairs and a whole pop. Having something come back quickly is part of having flexibility since things do go pear-shaped, and responding to outages rather than not having them is not tick box we get to decline. Today my Arista reloada in about 220 seconds which is tolerable but if it were half that I'd be even happier.
When I'm talking about "hardware initialization", I'm talking about the huge part that appends *before* the kernel boots. For example, hard-based RAID. On my server, when I push the start button, bios start-up, do a lot of awesome things (irony), start the raid (sloowly), and then, after 5min, pop up grub, then Linux, etc. 5min for hard (from power-on to grub), 20sec for software (from grub to prompt)
participants (6)
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George Herbert -
Jeffrey Ollie -
joel jaeggli -
Larry Sheldon -
nanog＠jack.fr.eu.org -
Simon Lyall