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systemd override.conf question
by Robert Moskowitz 25 Apr '17

25 Apr '17

Does the override.conf file need the section headers? For example: # cat /etc/systemd/system/postfix.service.d/override.conf [Unit] After=syslog.target network.target time-sync.target Will it work with just the After line, or is the [Unit] line needed to control the merge function. thanks

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Re: [CentOS] OT: systemd Poll - So Long, and Thanks for All the fish.
by James B. Byrne 24 Apr '17

24 Apr '17

On Wed, April 19, 2017 16:22, Chris Murphy wrote: > > Apple has had massively disruptive changes on OS X and iOS. Windows > has had a fairly disruptive set of changes in Windows 10. About the > only things that don't change are industrial OS's. > I have no idea how this reference applies to my earlier post. We do not use Apple or Windows servers and the desktop environment is stabilised at Win7pro. There will be be no Windows 10 here ever. OSX / iOS employment is limited to personal devices, none of which are permitted on premise in any case. > When it comes to breaking user space, there's explicit rules against > that in Linux kernel development. And internally consistent API/ABI > stability is something you're getting in CentOS/RHEL kernels, it's one > of the points the distributions exist. But the idea that Windows and > OS X have better overall API stability I think is untrue, having > spoken to a very wide assortment of developers who build primarily > user space apps. This may be true. It is likely important to software developers. It is also totally irrelevant to a business. Businesses, other than software development houses and consultants, are software users. When a vendor massively rearranges things in their software, deprecates scripting syntax that has existed for years if not decades, and fundamentally changes the way the administration of an operating system is presented it really matter not a wit to a business that the internal kernel level api remains unchanged. It is the accumulated administrative experience that is lost in consequence that concerns a business given that replacing that loss will cost either directly in retraining or indirectly in error and resultant disruption; or both. > > What does happen, in kernel ABI changes can break your driver, as > there's no upstream promise for ABI compatibility within the kernel > itself. The effect of this is very real on say, Android, and might be > one of the reasons for Google's Fuscia project which puts most of the > drivers, including video drivers, into user space. And Microsoft also > rarely changes things in their kernel, so again drivers tend to not > break. > > And this illustrates the point that I attempting to make. A business owner assumes that whatever OS is used it will deal with the various devices that make up its hardware environment. For if it does not then they seek an OS that does. However, vanishingly few firms in my experience (i.e.NONE) have ever had operational programming staff write or even modify a device driver. A business is in existence to make money for its owners not dick around with esoteric computer theory and practice. Red Hat, again in my sole opinion, increasingly appears to me to be emulating another company notorious for shuffling the user interface to little evident purpose other than profit. That is good business for them. It is not good for us. Bear in mind that we have been RedHat/Whitebox/CA-OS/CentOS users since 1998 so it is not like we are moving away from Linux with anything like enthusiasm. But this upgrade treadmill that has developed within RH is simply too costly for us to bear any longer. The idea that one has to rebuild from scratch entire host systems and then laboriously port over data and customised portions to a new host simply to upgrade the underlying OS is absolutely ludicrous. Consider the tremendous labour costs regularly incurred in accomplishing what amounts to maintaining the status quo. We just upgraded a FreeBSD host from 10.3 to 11.0 in situ without problem; and with very little downtime (three reboots in the space of 30 minutes). This was no standalone device either. It was the OS running the metal for multiple BHyve virtual machines, themselves running various operating systems (but mainly FreeBSD-11). One of said vms being our Samba-4 AD-DC. And, had it all gone south then, given we use ZFS in FreeBSD, and that we snapshot regularly, getting back to 10.3 would have been, and still could be, nearly instantaneous. Think about what that would take in terms of man hours to accomplish moving from EL6 to 7. And moving from 5 to 6 was not much better. This is just too expensive to repeat every three years. And allow me to forestall any claims that the chimera that is 'cloud computing' is the answer. All that does is make creating the requisite new platforms marginally less tedious. And that small advantage is purchased at the cost of handling over control of all your data to entities who are thoroughly discredited with respect to security and privacy. I am not anti or pro systemd, upstart, or etc/rc (or any other software although I admit to holding a generally dim view of things from Redmond). I do not really care what is used so long as it works and that introducing it does not greatly diminish the value of existing user skills and knowledge. However, I am past the point of patience with gratuitous changes that offer no appreciable benefit to the parties tasked with dealing them. Systemd is not the problem. It is a symptom of a deeper malaise, indifference. -- *** e-Mail is NOT a SECURE channel *** Do NOT transmit sensitive data via e-Mail Do NOT open attachments nor follow links sent by e-Mail James B. Byrne mailto:ByrneJB@Harte-Lyne.ca Harte & Lyne Limited http://www.harte-lyne.ca 9 Brockley Drive vox: +1 905 561 1241 Hamilton, Ontario fax: +1 905 561 0757 Canada L8E 3C3

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How to PXE kickstart hosts with little memory (Error: "Warning: /dev/root does not exist")?
by Frank Thommen 24 Apr '17

24 Apr '17

Hi, while kickstarting our virtual machines with PXE we often run into kickstart/anaconda failing with [...] [...] dracut-mount[xxx]: Warning: Can't mount root filesystem [...] dracut-mount[xxx]: Warning: /dev/root does not exist [...] dracut-mount[xxx]:/lib/dracut-lib.sh: line 1030: echo write error: No space left on device Starting Dracut Emergency Shell... Warning: /dev/root does not exist Generating "/run/initramfs/rsdosreport.txt" [...] It seems, that this is not related to local disk space - as I initally thought - but to too small memory. It only happens with VMs with little RAM (1024 MB). As soon as we raise the available memory to 2048 MB, kickstarting works fine. The RHEL 7 installation guide states, that the minimal memory requirement is 1 GB, so the network installation /should/ work. Is there a way to install such hosts w/o having to temporarily raise the available memory? Cheers frank

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Need a bit of 'archeocomputing' help on CentOS 7.
by Lamar Owen 24 Apr '17

24 Apr '17

I have an application with is binary-only, does its job well, and is only available for either libc5 (!) or early early glibc2.0 (!!). It has been running on a Red Hat Linux 5.2 (NOT RHEL; RHL) server for a really long time, and it honestly does its job and it's not easily replaced by an open-source solution at the moment. So, I need to do one of the following things: 1.) Run Red Hat Linux 5.2 (or similar vintage) on KVM on CentOS 7; 2.) Build libc5 (!) for CentOS 7 and run it on C7 (if that's even possible). The latest version of libc5 I know of that was shipped by Red Hat is in RHL 6.2, libc-5.3.12. (There is a 5.4, but not sure of stability or compatibility). So, I have RHL 5.2 (Apollo) running on KVM on C7, but I'm not getting any networking working. The only two non-virtio NICs are e1000 and rtl8139. As I recall kernel 2.0.36 and rtl8139 were pretty iffy together, and e1000 drivers are not likely available (I couldn't find any). The host's bridge sees the MAC of the guest, but the guest isn't seeing any traffic. So, has anyone tried doing anything this old with modern kvm (I'm using the qemu-ev packages, incidentally)? I've successfully set up the bridging; a CentOS 7 VM on the same host has full connectivity. So it's something about the rtl8139 and the 2.0.36 kernel. What is the oldest distribution you've done on KVM on C7?

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CentOS 7 + HPLIP = blank page
by Nicolas Kovacs 22 Apr '17

22 Apr '17

Hi, I just installed CentOS 7 + KDE on a new workstation in my office. I tried to setup my printer, but the test page is blank. Here's some details. The printer is an HP OfficeJet 8600 Pro. It works perfectly with all other desktop clients running Slackware Linux and HPLIP. I installed hplip and hplip-gui, launched HP Toolbox and then setup the printer - a network printer - which is mainly a matter of confirming OK, OK, OK. The printer shows up OK in HP Toolbox, but when I try to print a test page, the printer ejects a blank page, that's it. Which leaves me clueless. Cheers, Niki Kovacs -- Microlinux - Solutions informatiques durables 7, place de l'église - 30730 Montpezat Web : http://www.microlinux.fr Mail : info(a)microlinux.fr Tél. : 04 66 63 10 32

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Grub Prompt
by Allan E. Registos 22 Apr '17

22 Apr '17

Hi list, Good day to you all, Please correct me if this is the right list for posting this problem I am having with CentOS, but here is the details of the problem: I have a VMware guest running under Centos 6.5/64-bit. I rarely rebooted this OS, and was using it as my backend for some of my applications, like the A.R.T.(BI tool) and a PostgreSQL server. "But I was not unable to start the server because it now default to the grub prompt, here is what it look like: GNU GRUB version 0.97 (638K lower / 3143616K upper memory) [ Minimal BASH-like line editing is supported. For the first word, TAB lists possible command completions. Anywhere else TAB lists the possible completions of a device/filename.] grub> _ " I search google but the solutions provided does not solve this issue. Thank you, Allan

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nameserver issue
by Fred Smith 22 Apr '17

22 Apr '17

Hi all! This question is, at best, somewhat peripheral to Centos, but I'm hoping to be forgiven, and that someone here can give me a clue. I've just brought up a nameserver on my household LAN, bind9 on a Raspberry Pi. The connection with Centos is this: my main desktop is C7, and its hardwired network is also manual, not dhcp. I've edited the ipv4 config (in NM) and changed the DNS settings from 192.168.2.1 (the router) to 192.168.2.2 (the RPi). I've also manually tweaked /etc/resolv.conf to contain 192.168.2.2 instead of 192.168.2.1. works fine. until I fire up a vpn. having done that, looking in /etc/resolv.conf (while the vpn is connected) it has reverted to 192.168.2.1. after shutting down the vpn, 192.168.2.1 remains in resolv.conf what am I overlooking here? now the not-so-Centos-related question: I've changed the dhcp settings in my router so it should deliver 192.168.2.2 to the dhcp clients instead of 192.168.2.1. And it does, sorta. all the systems that use DHCP, now are configured with two DNS server addresses, 192.168.2.2, and 192.168.2.1. And I have no clue why 192.168.2.1 is still showing. Both windows and Linux systems are showing this behavior. Clues appreciated! and thanks in advance. -- ---- Fred Smith -- fredex(a)fcshome.stoneham.ma.us ----------------------------- But God demonstrates his own love for us in this: While we were still sinners, Christ died for us. ------------------------------- Romans 5:8 (niv) ------------------------------

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anaconda/kickstart: bonding device not created as expected
by Frank Thommen 21 Apr '17

21 Apr '17

Hi, I am currently struggling with the right way to configure a bonding device via kickstart (via PXE). I am installing servers which have "eno" network interfaces. Instead of the expected bonding device with two active slaves (bonding mode is balance-alb), I get a bonding device with only one active slave and an independent, non-bonded network device. Also the bonding device gets its MAC address from the second instead of from the first device. I appreciate any hint (or rtfm with the name of the correct fm ;-) on how to achieve the desired setup through kickstart. Please find the used PXE and kickstart settings and resulting network configuration below. I did this with CentOS 7.2.1511. We cannot go further due to Infiniband and lustre drivers which are currently only supported for this CentOS 7.x version Cheers frank -------------------------------------------------- The used PXE configuration is LABEL CentOS-7 kernel centos-7/vmlinuz append initrd=centos-7/initrd.img ip=dhcp nameserver=xx.xx.xx.xx ksdevice=eno1 inst.repo=http://our.mirror.server/7/os/x86_64 inst.ks.sendmac inst.ks=http://our.kickstart.server/ks.cgi and the network settings in the kickstart file are network --device bond0 --bondslaves=eno1,eno2 --bondopts=mode=balance-alb --bootproto=dhcp --hostname=myhost --activate I would have expected to get a bonding device with eno1 and eno2 as slave devices, the bonding device inheriting the MAC address from eno1 (otherwise DHCP won't work). Instead the result is a bonding device with eno2 as - sole - slave device and eno1 as a single active device with the main IP address of the host: bond0: flags=5187<UP,BROADCAST,RUNNING,MASTER,MULTICAST> mtu 1500 inet6 fe80::42f2:e9ff:fec7:b5f1 prefixlen 64 scopeid 0x20<link> ether 40:f2:e9:c7:b5:f1 txqueuelen 0 (Ethernet) RX packets 29 bytes 5274 (5.1 KiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 39 bytes 3486 (3.4 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 eno1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet xx.xx.xx.xx netmask 255.255.255.0 broadcast xx.xx.xx.xx inet6 fe80::42f2:e9ff:fec7:b5f0 prefixlen 64 scopeid 0x20<link> ether 40:f2:e9:c7:b5:f0 txqueuelen 1000 (Ethernet) RX packets 4303 bytes 798163 (779.4 KiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 1686 bytes 481585 (470.2 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 device interrupt 16 eno2: flags=6211<UP,BROADCAST,RUNNING,SLAVE,MULTICAST> mtu 1500 ether 40:f2:e9:c7:b5:f1 txqueuelen 1000 (Ethernet) RX packets 29 bytes 5274 (5.1 KiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 39 bytes 3486 (3.4 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 device interrupt 17 The ifcfg-files look basically ok, but there are two for the eno1 device. ifcfg of the bonding device: $ cat ifcfg-bond0 # Generated by parse-kickstart IPV6INIT="yes" DHCP_HOSTNAME="myhost" NAME="Bond connection bond0" BONDING_MASTER="yes" BOOTPROTO="dhcp" BONDING_OPTS="mode=balance-alb" DEVICE="bond0" TYPE="Bond" ONBOOT="yes" UUID="35910614-4a7c-43c9-8e44-dcf44b783358" $ ifcfg of the two slave devices $ cat ifcfg-bond0_slave_1 # Generated by parse-kickstart NAME="bond0 slave 1" MASTER="35910614-4a7c-43c9-8e44-dcf44b783358" HWADDR="40:f2:e9:c7:b5:f0" TYPE="Ethernet" ONBOOT="yes" UUID="f3a0a007-861c-42b6-8264-6efba62232ce" $ $ cat ifcfg-bond0_slave_2 # Generated by parse-kickstart NAME="bond0 slave 2" MASTER="35910614-4a7c-43c9-8e44-dcf44b783358" HWADDR="40:f2:e9:c7:b5:f1" TYPE="Ethernet" ONBOOT="yes" UUID="ee3f7c84-d4cb-412e-887d-6b1c753eb913" $ ifcfg of eno1 (which physically has the MAC address 40:f2:e9:c7:b5:f0, which is the same as ifcfg-bond0_slave_1 $ cat ifcfg-eno1 # Generated by dracut initrd NAME="eno1" DEVICE="eno1" ONBOOT=yes NETBOOT=yes UUID="d20645a0-8093-45f3-9630-d0249f76726b" IPV6INIT=yes BOOTPROTO=dhcp TYPE=Ethernet DNS1="192.55.188.177" $

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Problems With Booting CentOS on Dell T7910
by Paul E. Virgo 21 Apr '17

21 Apr '17

Hello! Does anyone have any experience with installing CentOS 6 (specfically, 6.8), on a Dell T7910? I've tried at least a dozen installs, everything gets configured, and when I have the system reboot, I get 'No boot device found press any key to reboot the machine'. In BIOS, I've enabled AHCI, Legacy boot and modes, and enabled the SAS controller. The disks are seen and written to. It uses a MPT SAS3 RAID controller, and I've even specified a 'diskdrive' statement pointing to the known drivers for the controller, and still nothing. This system is listed as compatible, but I don't know. Any suggestions or help appreciated.. -- Paul E Virgo Sr. System Administrator Code 610.2 SESDA III - DAAC/DISC Goddard Space Flight Ctr/NASA Greenbelt, MD Greenbelt, MD 20771 (301) 614-5751

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What besides Postfix should not start until system time set?
by Robert Moskowitz 21 Apr '17

21 Apr '17

So I have learned that Postfix should delay until Chronyd has moved the system time from 0 to current. What other services need to be delayed? Apache? Bind? Of course if this is a nameserver, Chronyd will probably not be able to resolve the NTP server addresses until Bind is running! thanks

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