Re: [CentOS] systemd override.conf question

[Robert Moskowitz]

On 04/24/2017 07:37 PM, Jonathan Billings wrote:

On Mon, Apr 24, 2017 at 06:35:38PM +0200, Robert Moskowitz wrote:

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.

It needs to know what section (such as [Unit], [Service] and
[Install]) the configuration option is in, so yes, it needs the [Unit]
line.



thanks


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[CentOS-virt] Issues with exposing USB serial dongle to guest VM

[Philip Prindeville]

Hi.

I have Centos 7 (updated) running as my host, and I’m using Qemu and KVM, 
version 2.0.0 and 2.6.0.

I have a Trendnet TU-S9 USB serial dongle attached to the host, which uses the 
Prolific 2303 chipset.

I blacklisted the pl2303 driver so the host doesn’t grab the device, and want 
to expose it to the guest.

On the client, I see 2 USB hubs (3.0 and 2.0), and I see 2 USB endpoints (even 
though 3 are configured).  So the USB CF card readers are visible, but not the 
USB dongle, even though it’s plugged in.

Here’s what I see on the host:

[philipp@kvm1 ~]$ ps -f -p13468
UIDPID  PPID  C STIME TTY  TIME CMD
qemu 13468 1  2 14:51 ?00:02:39 /usr/libexec/qemu-kvm -name 
guest=ubuntu16.04-2,debug-threads=on -S -object 
secret,id=masterKey0,format=raw,file=/var/lib/libvirt/qemu/domain-2-ubuntu16.04-2/master-key.aes
 -machine pc-i440fx-rhel7.3.0,accel=kvm,usb=off -cpu 
Broadwell,+vme,+ds,+acpi,+ss,+ht,+tm,+pbe,+dtes64,+monitor,+ds_cpl,+vmx,+smx,+est,+tm2,+xtpr,+pdcm,+dca,+osxsave,+f16c,+rdrand,+arat,+tsc_adjust,+xsaveopt,+pdpe1gb,+abm,+rtm,+hle
 -m 8192 -realtime mlock=off -smp 8,maxcpus=12,sockets=12,cores=1,threads=1 
-uuid a9590ac8-e532-4dce-b6ef-d3b35c0db865 -no-user-config -nodefaults -chardev 
socket,id=charmonitor,path=/var/lib/libvirt/qemu/domain-2-ubuntu16.04-2/monitor.sock,server,nowait
 -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc,driftfix=slew 
-global kvm-pit.lost_tick_policy=discard -no-hpet -no-shutdown -global 
PIIX4_PM.disable_s3=1 -global PIIX4_PM.disable_s4=1 -boot strict=on -device 
nec-usb-xhci,id=usb,bus=pci.0,addr=0x5 -device 
ich9-usb-ehci1,id=usb1,bus=pci.0,addr=0xa.0x7 -device 
virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x6 -drive 
file=/var/lib/libvirt/images/ubuntu16.04-2.img,format=raw,if=none,id=drive-virtio-disk0
 -device 
virtio-blk-pci,scsi=off,bus=pci.0,addr=0x7,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1
 -drive if=none,id=drive-ide0-0-0,readonly=on -device 
ide-cd,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0 -chardev 
pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -chardev 
spicevmc,id=charchannel0,name=vdagent -device 
virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=com.redhat.spice.0
 -spice 
port=5900,addr=127.0.0.1,disable-ticketing,image-compression=off,seamless-migration=on
 -device 
qxl-vga,id=video0,ram_size=67108864,vram_size=67108864,vram64_size_mb=0,vgamem_mb=16,bus=pci.0,addr=0x2
 -device intel-hda,id=sound0,bus=pci.0,addr=0x4 -device 
hda-duplex,id=sound0-codec0,bus=sound0.0,cad=0 -chardev 
spicevmc,id=charredir0,name=usbredir -device 
usb-redir,chardev=charredir0,id=redir0,bus=usb.0,port=1 -chardev 
spicevmc,id=charredir1,name=usbredir -device 
usb-redir,chardev=charredir1,id=redir1,bus=usb.0,port=2 -device 
usb-host,hostbus=3,hostaddr=13,id=hostdev1,bus=usb.0,port=3 -device 
usb-host,hostbus=3,hostaddr=12,id=hostdev2,bus=usb.0,port=4 -device 
usb-host,hostbus=3,hostaddr=15,id=hostdev3,bus=usb1.0,port=1 -device 
vfio-pci,host=07:10.0,id=hostdev0,bus=pci.0,addr=0x3 -device 
virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x8 -msg timestamp=on

[philipp@kvm1 ~]$ sudo lsof -p 13468 -n -P
COMMANDPID USER   FD  TYPE DEVICE SIZE/OFF   NODE 
NAME
qemu-kvm 13468 qemu  cwd   DIR  253,0  242 64 /
qemu-kvm 13468 qemu  rtd   DIR  253,0  242 64 /
qemu-kvm 13468 qemu  txt   REG  253,0  8883768  100834619 
/usr/libexec/qemu-kvm
qemu-kvm 13468 qemu  mem   REG  253,019984   34091991 
/usr/lib64/sasl2/libplain.so.3.0.0
qemu-kvm 13468 qemu  mem   REG  253,019984   34091988 
/usr/lib64/sasl2/liblogin.so.3.0.0
qemu-kvm 13468 qemu  mem   REG  253,057888   33916680 
/usr/lib64/sasl2/libdigestmd5.so.3.0.0
qemu-kvm 13468 qemu  mem   REG  253,024160   33916677 
/usr/lib64/sasl2/libcrammd5.so.3.0.0
qemu-kvm 13468 qemu  mem   REG  253,0  1846280  100701718 
/usr/lib64/libdb-5.3.so
qemu-kvm 13468 qemu  mem   REG  253,028200   33627120 
/usr/lib64/sasl2/libsasldb.so.3.0.0
qemu-kvm 13468 qemu  mem   REG  253,019952   33627117 
/usr/lib64/sasl2/libanonymous.so.3.0.0
qemu-kvm 13468 qemu  mem   REG  253,062184  100664409 
/usr/lib64/libnss_files-2.17.so
qemu-kvm 13468 qemu  mem   REG  253,068192  100701681 
/usr/lib64/libbz2.so.1.0.6
qemu-kvm 13468 qemu  mem   REG  253,099952  100701712 
/usr/lib64/libelf-0.166.so
qemu-kvm 13468 qemu  mem   REG  253,0   398264  100701630 
/usr/lib64/libpcre.so.1.2.0
qemu-kvm 13468 qemu  mem   REG  253,028360  100702508 
/usr/lib64/libogg.so.0.8.0
qemu-kvm 13468 qemu  mem   REG  253,0   189256  100882393 
/usr/lib64/libvorbis.so.0.4.6

[CentOS] kickstart: dracut-initqueue fails due to unresolvable hostname even though network config looks perfectly ok

[Frank Thommen]

Hi,

kickstarting fails due to problems with host resolution, even though the 
network seems to be properly configured through DHCP.  eno1 and eno2 are 
both attached to the network, but only eno1 gets an IP via DHCP.  Still 
`curl` cannot resolve the mirror host and the kickstart host during 
dracut-initqueue:


rdsosreport.txt

[...]
[   14.780428] localhost kernel: IPv6: ADDRCONF(NETDEV_UP): eno1: link 
is not ready
[   19.977052] localhost kernel: tg3 :0b:00.0 eno1: Link is up at 
1000 Mbps, full duplex
[   19.977118] localhost kernel: tg3 :0b:00.0 eno1: Flow control is 
off for TX and off for RX

[   19.978880] localhost kernel: tg3 :0b:00.0 eno1: EEE is disabled
[   19.980693] localhost kernel: IPv6: ADDRCONF(NETDEV_CHANGE): eno1: 
link becomes ready

[   19.829468] localhost dracut-initqueue[992]: dhcp: PREINIT eno1 up
[   19.853734] localhost dhclient[1393]: DHCPDISCOVER on eno1 to 
255.255.255.255 port 67 interval 6 (xid=0x4df19201)
[   26.030151] localhost dhclient[1393]: DHCPDISCOVER on eno1 to 
255.255.255.255 port 67 interval 13 (xid=0x4df19201)
[   26.033472] localhost dhclient[1393]: DHCPREQUEST on eno1 to 
255.255.255.255 port 67 (xid=0x4df19201)

[   26.033668] localhost dhclient[1393]: DHCPOFFER from 10.128.196.98
[   26.038851] localhost dhclient[1393]: DHCPACK from 10.128.196.98 
(xid=0x4df19201)

[   26.067534] localhost dracut-initqueue[992]: dhcp: BOND setting eno1
[   28.082735] localhost dhclient[1393]: bound to 10.128.196.20 -- 
renewal in 21301 seconds.

[   28.456131] localhost kernel: tg3 :0b:00.1: irq 153 for MSI/MSI-X
[   28.456149] localhost kernel: tg3 :0b:00.1: irq 154 for MSI/MSI-X
[   28.456165] localhost kernel: tg3 :0b:00.1: irq 155 for MSI/MSI-X
[   28.456180] localhost kernel: tg3 :0b:00.1: irq 156 for MSI/MSI-X
[   28.456196] localhost kernel: tg3 :0b:00.1: irq 157 for MSI/MSI-X
[   28.570450] localhost kernel: IPv6: ADDRCONF(NETDEV_UP): eno2: link 
is not ready
[   34.024621] localhost kernel: tg3 :0b:00.1 eno2: Link is up at 
1000 Mbps, full duplex
[   34.026347] localhost kernel: tg3 :0b:00.1 eno2: Flow control is 
off for TX and off for RX

[   34.028069] localhost kernel: tg3 :0b:00.1 eno2: EEE is disabled
[   34.029776] localhost kernel: IPv6: ADDRCONF(NETDEV_CHANGE): eno2: 
link becomes ready

[   33.803606] localhost dracut-initqueue[992]: dhcp: PREINIT eno2 up
[   33.827664] localhost dhclient[1570]: DHCPDISCOVER on eno2 to 
255.255.255.255 port 67 interval 7 (xid=0x1e8bdc4b)
[   41.000199] localhost dhclient[1570]: DHCPDISCOVER on eno2 to 
255.255.255.255 port 67 interval 15 (xid=0x1e8bdc4b)
[   55.588353] localhost dhclient[1570]: DHCPDISCOVER on eno2 to 
255.255.255.255 port 67 interval 18 (xid=0x1e8bdc4b)
[   74.172423] localhost dhclient[1570]: DHCPDISCOVER on eno2 to 
255.255.255.255 port 67 interval 12 (xid=0x1e8bdc4b)
[   86.446514] localhost dhclient[1570]: DHCPDISCOVER on eno2 to 
255.255.255.255 port 67 interval 9 (xid=0x1e8bdc4b)

[   95.253443] localhost dhclient[1570]: No DHCPOFFERS received.
[   95.253648] localhost dhclient[1570]: No working leases in persistent 
database - sleeping.

[   95.282175] localhost dracut-initqueue[992]: dhcp: FAIL
[   95.353255] localhost dracut-initqueue[992]: RTNETLINK answers: File 
exists
[  102.502688] localhost dracut-initqueue[992]: Warning: can't find 
installer mainimage path in .treeinfo
[  102.517568] localhost dracut-initqueue[992]: % Total% Received % 
Xferd  Average Speed   TimeTime Time  Current
[  102.525942] localhost dracut-initqueue[992]: Dload  Upload   Total 
SpentLeft  Speed
[  102.534277] localhost dracut-initqueue[992]: 0 00 00 
   0  0  0 --:--:-- --:--:-- --:--:-- 0Warning: Transient 
problem: timeout Will retry in 1 seconds. 3 retries left.
[  103.527190] localhost dracut-initqueue[992]: 0 00 00 
   0  0  0 --:--:-- --:--:-- --:--:-- 0Warning: Transient 
problem: timeout Will retry in 2 seconds. 2 retries left.
[  105.533677] localhost dracut-initqueue[992]: 0 00 00 
   0  0  0 --:--:-- --:--:-- --:--:-- 0Warning: Transient 
problem: timeout Will retry in 4 seconds. 1 retries left.
[  109.542329] localhost dracut-initqueue[992]: 0 00 00 
   0  0  0 --:--:-- --:--:-- --:--:-- 0curl: (6) Could not 
resolve host: our.centos.mirror; Unknown error
[  109.551613] localhost dracut-initqueue[992]: Warning: Downloading 
'http://our.centos.mirror/7.2.1511/os/x86_64/LiveOS/squashfs.img' failed!
[  109.615143] localhost dracut-initqueue[992]: % Total% Received % 
Xferd  Average Speed   TimeTime Time  Current
[  109.624698] localhost dracut-initqueue[992]: Dload  Upload   Total 
SpentLeft  Speed
[  109.625018] localhost dracut-initqueue[992]: 0 00 00 
   0  0  0 --:--:-- --:--:-- --:--:-- 0Warning: Transient 
problem: timeout Will retry 

Re: [CentOS] OT: systemd Poll - So Long, and Thanks for All the fish.

[Lamar Owen]

On 04/24/2017 11:52 AM, Warren Young wrote:

On Apr 24, 2017, at 7:53 AM, Lamar Owen  wrote:

James' point isn't the hardware cost, it's the people cost for retraining.

Unless you’ve hired monkeys so that you must train them to do their tasks by 
rote, that is a soft cost, not a hard cost.


Dollars are dollars.  An hour spent in training as one hour less to 'do 
work.'  (I'm intentionally playing devil's advocate here; I personally 
don't have a problem with the changes other than I now have to remember 
to check the OS type and version every time I log in to a server prior 
to issuing commands).

Note also that Byrne’s solution was to move to an entirely different OS, but we 
don’t hear about the “retraining cost” involved with that.  Surely it was a 
larger jump from C6 or C7 to FreeBSD 10 than from C6 to C7?
Guaranteed that it was a much larger jump.  Although I am tangentially 
reminded of Apollo Domain/OS 10 where the SysV/BSD/Aegis behavior was 
settable by changing an environment variable.



It’ll be interesting to see how much change FreeBSD gets in the next 7 years.


What is interesting to me, having just worked on a 20-year-old server 
stack last week, is how much hasn't changed as well as how much of what 
gets used a lot has changed (remember life before yum? How about early 
yum that needed to download individual headers?). But 90% of what I 
learned 30 years ago on Xenix System 3 for the Tandy 6000 still works 
(mainly because I still use vi :-)  ).


That depends on the organization and its goals. 


Very much true.  My IT department that I run has a bit of a reputation; 
our 'stock' answer to any IT question is rumored to be 'it depends.'  
YMMV, etc.



...dual-socket Opteron LS20 blades (10+ years old)...CentOS 7, once installed, 
works great...

That doesn’t really contradict my point.

First, I said “most” hardware, but you’ve gone and cherry-picked uncommonly 
durable hardware here; you’re probably out in +3 sigma territory.


Hey, I just picked what I have here, that's all.  I could also talk 
about our 2007, 2009, and 2010-vintage donated EMC Clariion hardware.  
We have gotten many Dell PowerEdge servers and Optiplex/Precision 
desktops donated to us; got 19 Dell PE1950's donated in a lot three 
years ago, and those are some of our best servers.  The last servers we 
actually bought were a pair of Dell PE6950's in 2007; a grant funded two 
of them plus VMware VI3 and a couple of EMC Clariion CX3-10c SANs.  (All 
of those are still running and still doing their jobs.)


I'd rather have a five-year-old Precision than a 2017-model generic 
desktop.  A bit slower, but it's going to last a whole lot longer. For 
my own personal use I never buy new; I'll take the same money that would 
buy a low-end current-year marvel and buy a three to five year-old 
Precision that will run faster and much longer.  My current laptop is a 
Precision M6700 with a Core i7-3740QM.  It was $600 and will run rings 
around anything built today at that price point (and even twice or 
thrice that price point I dare say!).


But we're talking servers here, and the LS20 blade for the BladeCenter 
is middle-of-the-road as far as server hardware is concerned.  The 
PE1950 is on the lower side of MOR.



A lot of commodity PC-grade SOHO “server” hardware won’t even last the 3 years 
between major CentOS upgrades before dying of something.  There was a period 
where I’d budget 1-2 years for a Netgear switch, for example.  (They appear to 
be lasting longer now.)


I haven't looked at the lower end of the server hardware scale in a long 
time, although we did get some older low-end Dell PE SC1425's donated to 
us a while back.  They run C7 quite well, too.  I'd rather buy a used 
higher-end box than a new low-end box, which is going to both cost more 
and wear out sooner.


But that's just SOP for a non-profit.


Second, the application of my quoted opinion to your situation is that you 
should run that hardware with CentOS 7 through the EOL of the hardware or 
software, whichever comes first.  That is, I’m advising the change-adverse 
members of the audience to opt into the second group above, taking OS changes 
in big lumps when it’s time to move to new hardware anyway.
There is no easy solution.  The sysadmin's work and continuing education 
is never done.  I don't mind learning new things nor is my budgeted time 
so tight that I can't spend company time getting familiar with newer 
admin paradigms.  I understand that everyone is not like me (which is 
probably a good thing).


The sysadmin 'political landscape' is not too different from the 
'regular' political landscape, really.  You have conservatives, and you 
have progressives.  They both think they're right, and they both tend to 
demonize those who disagree.  And both are growing more extremist with 
time.  Is there no middle ground to be had (in the sysadmin world, at 
least)?


I certainly understand and sympathize with James' 

Re: [CentOS] sha256sum a dvd

[Jonathan Billings]

On Mon, Apr 24, 2017 at 12:53:36PM -0400, James B. Byrne wrote:
>
> CentOS-6.9
> 
> I am trying to verify a locally created dvd.  I am using sha256sum in
> this fashion:
> sha256sum /dev/sr0
> 
> Which gave this result:
> 
> sha256sum: /dev/sr0: Input/output error
> 
> 
> So I tried this:
> sha256sum /dev/cdrom
> 
> Which, after some time, also produces:
> 
> sha256sum: /dev/cdrom: Input/output error
> 
> What does this mean and how do I fix it?

It means that you're getting an error while reading one of the sectors
of the DVD.  It might be a problem with the disc, but it could also be
a problem with the hardware.

Try doing a dd to copy all the bits to a local file, and pay attention
to see if it has a problem reading the disc.  Then run a sha256sum on
the file it created.  

-- 
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Re: [CentOS] systemd override.conf question

[Jonathan Billings]

On Mon, Apr 24, 2017 at 06:35:38PM +0200, Robert Moskowitz wrote:
> 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.

It needs to know what section (such as [Unit], [Service] and
[Install]) the configuration option is in, so yes, it needs the [Unit]
line. 

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Re: [CentOS] OT: systemd Poll - So Long, and Thanks for All the fish.

[Valeri Galtsev]

On Mon, April 24, 2017 10:52 am, Warren Young wrote:
> On Apr 24, 2017, at 7:53 AM, Lamar Owen  wrote:
>> James' point isn't the hardware cost, it's the people cost for
>> retraining.
>
> Unless you’ve hired monkeys so that you must train them to do their
tasks by rote, that is a soft cost, not a hard cost.  If you’ve hired
competent IT staff, they will indeed need some time to work out the
differences, but they will do that on their own if only given that time.

I've been through that, I agree almost on all counts with James Byrne, so
I can give some comments from my chair here. Yes, I do consider myself a
notch more intelligent sysadmin than a monkey, and it does cost me time to
adjust to the differences, and it is annoying, and most annoying is to
adjust to some changes in philosophy (whoever considers the last
non-existent is allowed to re-qualify me back to the level of monkey ;-)

>
> Note also that Byrne’s solution was to move to an entirely different
OS,
> but we don’t hear about the “retraining cost” involved with that. 
Surely it was a larger jump from C6 or C7 to FreeBSD 10 than from C6 to
C7?

Yes and no. Maybe it is just my case, as I stared migrating servers to
FreeBSD even before C7 was released. FreeBSD feels closer to C5, whereas
difference between C5 and C7 is more dramatic (in my by no means objective
feeling). So, everyone who maintained C5 after quick "jump start" may feel
at hone with FreeBSD. My case may be even simpler as as many older
sysadmins I maintained a few UNIXes in the past, including FreeBSD.

>
> He also seems to be sweeping aside the fact that FreeBSD major releases
generally stay in support for about half the span of RHEL and its
derivatives.

True, but keeping your system incrementing in smaller steps that happen
more often is not a big deal. But this is a question of taste: both long
support life like RHEL and CentOS and shorter but smoother changes like
FreeBSD or some Linuxes (Debian and its clone Ubuntu come to mind) - they
both have their advantages and their place where they shine.

>  If he wants to stay on a supported OS the whole time that C7
> remains in support, he’s probably looking at 2 major OS version upgrades.

I've been through several FreeBSD major version upgrades on servers I
migrated to FreeBSD earliest, and they went smoothly, requiring just 3
reboots in the process. They all had a bunch of jails that were upgraded
as well. Not a single major issue that I had to resolve in a process (call
me lucky... knocking on wood ;-)

>
> It’ll be interesting to see how much change FreeBSD gets in the next 7
years.

It really is. Unless my usual luck in choosing what I expect to be in a
future fails me, not much change will happen to FreeBSD. I was thanking my
luck big time for choosing RedHat (and continuing to Fedora, then CentOS)
instead of Debian once when big flop in Debian (and all clones) was
discovered that was sitting there for over two years (search for Debian
predictable keys). My Debian friend was re-creating all his certificates,
re-generating ssh keys, rebuilding systems from scratch (as you don't know
who might have had root access to your box). And I was repeating myself,
that RedHat never had such a big flop. So I hope, I will be the same lucky
with my choice of FreeBSD as I was with my choice of RedHat (and clones)
back then.

And while we are here: My big thanks to RedHat, and big thanks to CentOS
team for the great job you guys are doing!! I wish I could help you more
than just maintaining CentOS and centosvault public mirrors.

Valeri

>
>> In many ways the Fedora treadmill is easier, being that there are many
more smaller jumps than the huge leap from C6 to C7.
>
> That depends on the organization and its goals.
>
> If you have a true IT staff that exists just to keep servers up to date
and working properly, then yes, you’re right, smaller upgrades every
3-6
> months are often easier to handle than trying to choke down 2-10 years
of
> changes all at once, depending on the LTS release strategy and how many
major upgrades you skip.
>
> If you’re trying to treat the OS as a base atop which you do something
else, and you just need something that will keep working for 2-10 years
despite being continually patched, then choking that big ball of changes
down every 2-10 years might be preferable.
>
> My main point is that if you’re going to take the second path, don’t
cry about how much change there is to choke down when you’re finally
forced to move forward.  You choose to put off dealing with it for many
years; the chickens have come back home to roost, so there will of
course
> be a lot of work to do.
>
>> ...dual-socket Opteron LS20 blades (10+ years old)...CentOS 7, once
installed, works great...
>
> That doesn’t really contradict my point.
>
> First, I said “most” hardware, but you’ve gone and cherry-picked
uncommonly durable hardware here; you’re probably out in +3 sigma
territory.  A lot 

[CentOS] sha256sum a dvd

[James B. Byrne]

CentOS-6.9

I am trying to verify a locally created dvd.  I am using sha256sum in
this fashion:
sha256sum /dev/sr0

Which gave this result:

sha256sum: /dev/sr0: Input/output error


So I tried this:
sha256sum /dev/cdrom

Which, after some time, also produces:

sha256sum: /dev/cdrom: Input/output error

What does this mean and how do I fix it?


-- 
***  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. Byrnemailto:byrn...@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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[CentOS] systemd override.conf question

[Robert Moskowitz]

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] How to PXE kickstart hosts with little memory (Error: "Warning: /dev/root does not exist")?

[Frank Thommen]

On 04/21/2017 10:25 PM, Gordon Messmer wrote:

On 04/21/2017 12:49 PM, Frank Thommen wrote:


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.


Yeah, I filed a bug report against the documentation some time ago.

https://bugzilla.redhat.com/show_bug.cgi?id=1410948

...though bugzilla is currently down.


Is there a way to install such hosts w/o having to temporarily raise
the available memory?



None that I'm aware of, as of 7.3.  If you have a 7.2 install tree, you
can boot the older installer and then update the installed system.
Seems easier to boost the memory, typically.


I gave it a try with 7.2.1511 and that works fine as long as I have 
"ip=eth0:dhcp" in my PXE config.  As soon as I expand it to 
"ip=eth0:dhcp ip=eno1:dhcp rd.neednet=1" (I do that to make sure 
kickstart works independently from the name of the network interface), 
kickstart enters into emergency mode w/o any error message after a lot 
of timeout warnings.  However that's something we can work around.


Thanks for the 7.2 hint.

frank


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Re: [CentOS] OT: systemd Poll - So Long, and Thanks for All the fish.

[Warren Young]

On Apr 24, 2017, at 7:53 AM, Lamar Owen  wrote:
> 
> James' point isn't the hardware cost, it's the people cost for retraining.

Unless you’ve hired monkeys so that you must train them to do their tasks by 
rote, that is a soft cost, not a hard cost.  If you’ve hired competent IT 
staff, they will indeed need some time to work out the differences, but they 
will do that on their own if only given that time.

Note also that Byrne’s solution was to move to an entirely different OS, but we 
don’t hear about the “retraining cost” involved with that.  Surely it was a 
larger jump from C6 or C7 to FreeBSD 10 than from C6 to C7?

He also seems to be sweeping aside the fact that FreeBSD major releases 
generally stay in support for about half the span of RHEL and its derivatives.  
If he wants to stay on a supported OS the whole time that C7 remains in 
support, he’s probably looking at 2 major OS version upgrades.

It’ll be interesting to see how much change FreeBSD gets in the next 7 years.

> In many ways the Fedora treadmill is easier, being that there are many more 
> smaller jumps than the huge leap from C6 to C7.

That depends on the organization and its goals.

If you have a true IT staff that exists just to keep servers up to date and 
working properly, then yes, you’re right, smaller upgrades every 3-6 months are 
often easier to handle than trying to choke down 2-10 years of changes all at 
once, depending on the LTS release strategy and how many major upgrades you 
skip.

If you’re trying to treat the OS as a base atop which you do something else, 
and you just need something that will keep working for 2-10 years despite being 
continually patched, then choking that big ball of changes down every 2-10 
years might be preferable.

My main point is that if you’re going to take the second path, don’t cry about 
how much change there is to choke down when you’re finally forced to move 
forward.  You choose to put off dealing with it for many years; the chickens 
have come back home to roost, so there will of course be a lot of work to do.

> ...dual-socket Opteron LS20 blades (10+ years old)...CentOS 7, once 
> installed, works great...

That doesn’t really contradict my point.

First, I said “most” hardware, but you’ve gone and cherry-picked uncommonly 
durable hardware here; you’re probably out in +3 sigma territory.  A lot of 
commodity PC-grade SOHO “server” hardware won’t even last the 3 years between 
major CentOS upgrades before dying of something.  There was a period where I’d 
budget 1-2 years for a Netgear switch, for example.  (They appear to be lasting 
longer now.)

Second, the application of my quoted opinion to your situation is that you 
should run that hardware with CentOS 7 through the EOL of the hardware or 
software, whichever comes first.  That is, I’m advising the change-adverse 
members of the audience to opt into the second group above, taking OS changes 
in big lumps when it’s time to move to new hardware anyway.
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Re: [CentOS] Need a bit of 'archeocomputing' help on CentOS 7.

[Warren Young]

On Apr 21, 2017, at 10:11 AM, Lamar Owen  wrote:
> 
> 1.) Run Red Hat Linux 5.2 (or similar vintage) on KVM on CentOS 7;

For what it’s worth, I couldn’t get it working under a modern flavor of VMware, 
either.  I find that telling because VMware tends to have the best driver 
support of all the VM systems, if only because it’s been around the longest.

Unfortunately, current VMware appears to have dropped Linux 2.0 support 
entirely, along with other contemporaneous things.  For instance, even the 
“legacy Linux” version of its VMware Tools package contains Perl scripts that 
are written with the assumption that they’re running on at least Perl 5.8, 
which is contemporaneous with RHL 7.3 and kernel 2.4.18.

I spent some time trying to backport those scripts to the Perl 5.004 that ships 
with RHL 5.2, but gave up after making over a dozen changes with no obvious end 
in sight.

The way I see it, your solution involving CentOS 2.1 and the libc5 
compatibility libraries just bought you the last upgrade to your software that 
you are likely to pull off without heroic efforts.  I advise you to use CentOS 
7’s remaining supported lifetime to get off this old software somehow.

You say there is no open source alternative, yet clearly the software was 
useful to at least you, and probably others, given that it appears to be 
commercial software.  It might be prudent to sponsor the development of an open 
source replacement system.

> e1000 drivers are not likely available (I couldn't find any).

That series of adapters didn’t get Linux support until about 2 years after RHL 
5 shipped, according to the sources:


http://lxr.free-electrons.com/source/drivers/net/ethernet/intel/e1000/e1000_main.c

That would make the e1000 driver about ~3 years too late for you.
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Re: [CentOS] OT: systemd Poll - So Long, and Thanks for All the fish.

[Lamar Owen]

On 04/20/2017 05:55 PM, Warren Young wrote:
... I find that most hardware is ready to fall over by the time the 
CentOS that was installed on it drops out of support anyway.

...


James' point isn't the hardware cost, it's the people cost for 
retraining.  In many ways the Fedora treadmill is easier, being that 
there are many more smaller jumps than the huge leap from C6 to C7. For 
the most part, however, I agree with most of your post.  I strongly 
disagree with the paragraph above, though.


I have worked for non-profits for most of my career thus far, which 
spans almost 30 years.  Non-profits by their very nature live on the 
slimmest of margins, and donations of hardware by individuals and 
companies have been in my experience the bread and butter for obtaining 
server-quality hardware.  The typical donation will be at least one or 
two generations old before the non-profit gets it; my current employer 
is just putting in production some IBM BladeCenters with the dual-socket 
Opteron LS20 blades (10+ years old).  Given the spiky workload, these 
blades are suitable for the targeted use, and the electrical 
requirements aren't a problem (I've done the math; it would take ten 
years or more to justify the purchase price of a new blade based on 
power savings alone, and our power is quite inexpensive here).  At least 
I can use very recent blades, and the eBay prices for 5-year-old blades 
are pretty good, so when I need that much more power I can get it.


Oh, and the LS20 blades are built like tanks.  We have a couple hundred 
of them that were donated, and we're going to use them.


For what it's worth, CentOS 7, once installed, works great as long as 
the lack of a GUI console isn't a problem (something with the 
BladeCenter's KVM switch and C7's kernel keeps the keyboard from working 
properly).


And don't even get me started on networking equipment, where I still 
have Catalyst 5500-series hardware in production.  (going on 20 years 
old and still trucking!)


And having said that, I just pulled out of service a server for another 
non-profit that had a power supply fan seize.  I posted about moving its 
application Friday.  It is an AMD K6-2/400 with a Western Digital 6GB 
boot drive and a Maxtor 30GB data drive, running Red Hat Linux 5.2.  The 
Antec power supply was put into service in 1999.  It stopped working 
Friday, and could have probably been put back into operation with a new 
power supply without a huge amount of work, but I decided it was time.  
Heh, it was time ten years ago!


The 6GB WD drive was only 19 years old; while I honestly wanted to see 
it turn 20, it was time (power supply glitches caused by overheating of 
the power supply; worst-case for hard disk death in my experience).  
Yeah, 24x7 operation for 19 years with minimal downtime.  I'm going to 
personally put it back into service for hysterical raisins, since the 
VA-503+ board doesn't need re-cap and it runs very well for what it is.  
I'm not sure what I'm going to run on it yet.  (It will be in service 
for the same reasons I'm going to put a Reh CPU280 running UZI280 into 
service.).




And that’s why I use *all* the major OSes and several weird ones besides.  None 
of it is perfect, yet it all has its place.

I couldn't agree more.

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[CentOS-virt] qemu-kvm-ev update

[Neil Wilson]

How long does last week's security update remain in the test repo before it 
gets moved to release?

Rgs

Neil Wilson


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