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1608 discussions

CentOS Images on AWS with partitions on /dev/xvda1 are awkwared to resize
by Nico Kadel-Garcia 30 Apr '15

30 Apr '15

I'm staring at the free CentOS images on AWS, and seeing that whoever set those up elected to use a partition for /dev/xvda1 rather than taking advantage of Amazon's tendency to use "/dev/xvda", "/dev/xvdb", etc. for each disk and use those directly as a file system. The result is that if you elect to allocate a larger base disk image, for example allocating 50 Gig to allow local home directories or space for "mock" or for bulky logs, and don't spend the time to select and allocate new disk images, it's awkward to simply expand the "/" partition. And with only 8 Gig allocated in the latest CentOS 6 images that I see in AWS, it's possible to get pretty pressed for space pretty quickly. Now, AWS published guidelines on manipulating partition size, and expanding a matching filesystem, but they're very clear to "unmount the parition before you touch it!!!" That's a bit difficult to unmount with a "/" partition, and they understandably don't have the kind of "boot from CD and work from the console" setup I'd normally use for that kind of work. So: why did the creators of that CentOS AMI elect to use such a small / partition? And how dangerous is it, with the system essentially idle, to use "parted" to expand the "/dev/xvda1" parition and then use "resize2fs" to expand the "/" file system while the system is alive? Note that, because I'm a complete weasel, I know at least one way around this: add a second disk, copy the OS to *that*, set grub to boot from the second disk, reboot from that, paritition the first disk as desired, copy the OS back, reset grub to boot from the first disk, and pray. I've had good success with the approach in the past, and have rebuilt rougly 15,000 Linux systems this way. But the work predates CentOS, and I dont't want to go through that again. So, has anyone resized "/" successfully and gracefully on AWS CentOS instances? Nico Kadel-Garcia

3 6

ipv6 routing problem
by Khapare Joshi 30 Apr '15

30 Apr '15

I have centos 6 running kvm. IPv4 works perfectly works. But I am having some problem with ipv6, looks like its bridge routing problem but stuck. here are my bridge detail: bridge name bridge id STP enabled interfaces br0 8000.000af75613f2 no eth1 vnet1 br4 8000.000af75613f0 no eth0 ip -6 route shows : unreachable ::/96 dev lo metric 1024 error -101 mtu 65536 advmss 65476 hoplimit 4294967295 unreachable ::ffff:0.0.0.0/96 dev lo metric 1024 error -101 mtu 65536 advmss 65476 hoplimit 4294967295 unreachable 2002:a00::/24 dev lo metric 1024 error -101 mtu 65536 advmss 65476 hoplimit 4294967295 unreachable 2002:7f00::/24 dev lo metric 1024 error -101 mtu 65536 advmss 65476 hoplimit 4294967295 unreachable 2002:a9fe::/32 dev lo metric 1024 error -101 mtu 65536 advmss 65476 hoplimit 4294967295 unreachable 2002:ac10::/28 dev lo metric 1024 error -101 mtu 65536 advmss 65476 hoplimit 4294967295 unreachable 2002:c0a8::/32 dev lo metric 1024 error -101 mtu 65536 advmss 65476 hoplimit 4294967295 unreachable 2002:e000::/19 dev lo metric 1024 error -101 mtu 65536 advmss 65476 hoplimit 4294967295 2a00:c88:4000:1431::/64 dev br0 proto kernel metric 256 mtu 1500 advmss 1440 hoplimit 4294967295 2a00:c88:4000:1650::/64 dev br4 proto kernel metric 256 mtu 1500 advmss 1440 hoplimit 4294967295 unreachable 3ffe:ffff::/32 dev lo metric 1024 error -101 mtu 65536 advmss 65476 hoplimit 4294967295 fe80::/64 dev vnet0 proto kernel metric 256 mtu 1500 advmss 1440 hoplimit 4294967295 fe80::/64 dev vnet1 proto kernel metric 256 mtu 1500 advmss 1440 hoplimit 4294967295 fe80::/64 dev vnet2 proto kernel metric 256 mtu 1500 advmss 1440 hoplimit 4294967295 fe80::/64 dev vnet3 proto kernel metric 256 mtu 1500 advmss 1440 hoplimit 4294967295 fe80::/64 dev eth0 proto kernel metric 256 mtu 1500 advmss 1440 hoplimit 4294967295 fe80::/64 dev eth1 proto kernel metric 256 mtu 1500 advmss 1440 hoplimit 4294967295 fe80::/64 dev br0 proto kernel metric 256 mtu 1500 advmss 1440 hoplimit 4294967295 fe80::/64 dev br4 proto kernel metric 256 mtu 1500 advmss 1440 hoplimit 4294967295 default via 2a11:c99:4111:110::11:211 dev br4 metric 1 mtu 1500 advmss 1440 hoplimit 4294967295 Then I added, /etc/sysconfig/network-script/ifcfg-br4 DEVICE=br4 TYPE=Bridge ONBOOT=yes BOOTPROTO=static IPADDR=ipv4address here NETMASK=255.255.255.0 DNS1=mydnsserver.org DELAY=0 NM_CONTROLLED=no IPV6INIT=yes IPV6_AUTOCONF=no #IPV6_DEFROUTE="yes" IPV6_FAILURE_FATAL=yes IPV6ADDR=2a11:c99:4111:110::11:65/64 IPV6_DEFAULTGW= 2a11:c99:4111:110::11:211 I can ping the gateway from the kvm host but I cannot ping6 out from the kvm guest, also I cannot ping kvm guest from external host that is in ipv6 network. I appreciate some guidance on this.

1 0

Recommendations for virt on Opteron 275 systems.
by Lamar Owen 30 Apr '15

30 Apr '15

Hello, CentOS-virt list. The institution where I work has been donated some older IBM BladeCenters with IBM's LS-20 blade servers installed. These LS-20's are equipped with Opteron 275 processors (dual-core, dual-socket). In researching my virtualization options, I initially wanted to do oVirt, but after thoroughly investigating, it appears that oVirt, being based on KVM, will not work due to the Opteron 275 not supporting AMD-V virtualization extensions. So, further investigation showed that Xen4CentOS, using paravirtualization, should be supportable. So I'm looking for advice on deployment, including some pointers to some howtos or other documents on how to go about setting up a moderately large virtualization farm with Xen4CentOS on up to 200+ LS-20 blades, most of which have smallish internal storage, but with iSCSI connectivity to an EMC SAN; the deployment would start small and would grow as needed. I'm looking for the ability to do HA-type things, live migration, etc, to replace an aging VMware ESX setup. Windows guests are not a requirement. Pointers to solid VM management tools, especially for the HA and live migration options, would be nice. Purchasing upgraded blade servers isn't really an option for us at this time. (Now, if you or your organization wanted to donate some HS-21's or later, we would be glad to accept them; we are a 501(c)(3) not-for-profit public foundation...... :-) and then I could run oVirt).

1 0

Can we get a copy of ks.cfg for varous images into /root/ks.cfg?
by Nico Kadel-Garcia 28 Apr '15

28 Apr '15

I've recently been dealing with various CentOS images on AWS, and am being forcibly reminded that the "/root/anaconda-ks.cfg" has only a passing resemblance to whatever the kickstart configuration file actually contained. But getting a copy of the actual "ks.cfg" is invaluable for updating and testing variations of the kickstart setup, especially when manipulating disk partitioning or package selection. In particular, anaconda-ks.cfg fails to include any but the first '%post' script and discards all comments that may have been in the original ks.cfg file. Coupled with the problems of system-config-kickstart, and you have no provenance for the kickstart file that was actually *used* to create a particular system. For people building kickstart based environments, what would it take to get you to put this in your ks.cfg? %post cp /tmp/ks.cfg /mnt/sysimage/root/ks.cfg %end For older releases, '%end' is not needed. And before anyone asks, *YES* I've reached out to the anaconda developers in the past about this. I can try again, but in the meantime, it would really help me, and I think it would help others. Nico Kadel-Garcia

3 3

libvirtd for el7
by Sandro Bonazzola 24 Apr '15

24 Apr '15

Hi, I see that for EL6 gwd already has pushed a libvirtd package with version 1.2.10[1]. I got request from VDSM development to provide libvirt >= 1.2.9 for EL7 for oVirt 3.6. gwd, do you just rebuilt http://koji.fedoraproject.org/koji/buildinfo?buildID=594825 ? I'm looking at http://koji.fedoraproject.org/koji/buildinfo?buildID=628689 may this work for you? [1] http://cbs.centos.org/koji/buildinfo?buildID=251 -- Sandro Bonazzola Better technology. Faster innovation. Powered by community collaboration. See how it works at redhat.com

3 3

Updating to Xen 4.4.2
by Pasi Kärkkäinen 22 Apr '15

22 Apr '15

Hello, Sorry I've missed the last virt-sig meetings. Are we already working on updating the el6 rpms to Xen 4.4.2 ? Thanks, -- Pasi

2 4

Re: [CentOS-virt] CentOS 7 AMI Building
by yassine kool 21 Apr '15

21 Apr '15

Envoyé à partir de mon Windows Phone -----Message d'origine----- De : "Jason Antman" <jason(a)jasonantman.com> Envoyé : ‎17/‎04/‎2015 06:23 À : "Discussion about the virtualization on CentOS" <centos-virt(a)centos.org> Objet : Re: [CentOS-virt] CentOS 7 AMI Building Ok, thanks so much! That'll do fine. The only other bits mentioned on http://wiki.centos.org/Cloud/AWS in "Image Builder Notes" were the random root password, SELinux enabled, and relabel at first boot, which are easy enough. Thanks so much, Jason On Fri, Apr 17, 2015 at 12:20 PM, Karanbir Singh <mail-lists(a)karan.org> wrote: I highly recommend actually looking at the images :) its just a minimal install with cloud-init from extras/ added in ( for 7, the 6 ones dont have cloud-init ). the installed content delivered from the minimal.iso and the ami's should be identical in pretty much every respect. If you really want a kickstart for it, I can build one, but just run a minimal.iso install, add cloud-init to the %packages and bob's your uncle. On 16/04/15 17:48, Jason Antman wrote: > Yes... we currently use Packer to achieve a repeatable build process, > from scratch. We'd like to replicate that and be able to build from > scratch without spinning up an EC2 instance, in an automated way. > > I don't know how to phrase this, so apologies if it comes across wrong, > I have immense respect for you personally and for CentOS... but, is it > really that difficult to post the kickstarts and/or build scripts > somewhere? Or at least enough of them to replicate something similar? > > Thanks, > Jason > > On Thu, Apr 16, 2015 at 3:56 AM, Karanbir Singh <mail-lists(a)karan.org > <mailto:mail-lists@karan.org>> wrote: > > On 04/14/2015 12:48 PM, Jason Antman wrote: > > Hello, > > > > I'm new to this list, but I noticed a post from March 30th inquiring > > about the build scripts for the official CentOS7 AMIs. I'm also > > interested in this; I'm tasked with (unfortunately) spinning up some VMs > > in our corporate VMWare environment that are "as close as possible" to > > the official CentOS7 AMIs. I could attempt to reverse-engineer them and > > do you need to do much more than qemu-img convert -O vmdk > <centos-genericcloud.qcow2> ? > > > -- > Karanbir Singh > +44-207-0999389 <tel:%2B44-207-0999389> | http://www.karan.org/ | > twitter.com/kbsingh <http://twitter.com/kbsingh> > GnuPG Key : http://www.karan.org/publickey.asc > _______________________________________________ > CentOS-virt mailing list > CentOS-virt(a)centos.org <mailto:CentOS-virt@centos.org> > http://lists.centos.org/mailman/listinfo/centos-virt > > > > > _______________________________________________ > CentOS-virt mailing list > CentOS-virt(a)centos.org > http://lists.centos.org/mailman/listinfo/centos-virt > -- Karanbir Singh +44-207-0999389 | http://www.karan.org/ | twitter.com/kbsingh GnuPG Key : http://www.karan.org/publickey.asc _______________________________________________ CentOS-virt mailing list CentOS-virt(a)centos.org http://lists.centos.org/mailman/listinfo/centos-virt

1 0

Re: [CentOS-virt] CentOS 7 AMI Building
by yassine kool 21 Apr '15

21 Apr '15

Envoyé à partir de mon Windows Phone ________________________________ De : Jason Antman<mailto:jason@jasonantman.com> Envoyé : ‎17/‎04/‎2015 06:23 À : Discussion about the virtualization on CentOS<mailto:centos-virt@centos.org> Objet : Re: [CentOS-virt] CentOS 7 AMI Building Ok, thanks so much! That'll do fine. The only other bits mentioned on http://wiki.centos.org/Cloud/AWS in "Image Builder Notes" were the random root password, SELinux enabled, and relabel at first boot, which are easy enough. Thanks so much, Jason On Fri, Apr 17, 2015 at 12:20 PM, Karanbir Singh <mail-lists(a)karan.org> wrote: > I highly recommend actually looking at the images :) > > its just a minimal install with cloud-init from extras/ added in ( for > 7, the 6 ones dont have cloud-init ). > > the installed content delivered from the minimal.iso and the ami's > should be identical in pretty much every respect. If you really want a > kickstart for it, I can build one, but just run a minimal.iso install, > add cloud-init to the %packages and bob's your uncle. > > On 16/04/15 17:48, Jason Antman wrote: > > Yes... we currently use Packer to achieve a repeatable build process, > > from scratch. We'd like to replicate that and be able to build from > > scratch without spinning up an EC2 instance, in an automated way. > > > > I don't know how to phrase this, so apologies if it comes across wrong, > > I have immense respect for you personally and for CentOS... but, is it > > really that difficult to post the kickstarts and/or build scripts > > somewhere? Or at least enough of them to replicate something similar? > > > > Thanks, > > Jason > > > > On Thu, Apr 16, 2015 at 3:56 AM, Karanbir Singh <mail-lists(a)karan.org > > <mailto:mail-lists@karan.org>> wrote: > > > > On 04/14/2015 12:48 PM, Jason Antman wrote: > > > Hello, > > > > > > I'm new to this list, but I noticed a post from March 30th > inquiring > > > about the build scripts for the official CentOS7 AMIs. I'm also > > > interested in this; I'm tasked with (unfortunately) spinning up > some VMs > > > in our corporate VMWare environment that are "as close as > possible" to > > > the official CentOS7 AMIs. I could attempt to reverse-engineer > them and > > > > do you need to do much more than qemu-img convert -O vmdk > > <centos-genericcloud.qcow2> ? > > > > > > -- > > Karanbir Singh > > +44-207-0999389 <tel:%2B44-207-0999389> | http://www.karan.org/ | > > twitter.com/kbsingh <http://twitter.com/kbsingh> > > GnuPG Key : http://www.karan.org/publickey.asc > > _______________________________________________ > > CentOS-virt mailing list > > CentOS-virt(a)centos.org <mailto:CentOS-virt@centos.org> > > http://lists.centos.org/mailman/listinfo/centos-virt > > > > > > > > > > _______________________________________________ > > CentOS-virt mailing list > > CentOS-virt(a)centos.org > > http://lists.centos.org/mailman/listinfo/centos-virt > > > > > -- > Karanbir Singh > +44-207-0999389 | http://www.karan.org/ | twitter.com/kbsingh > GnuPG Key : http://www.karan.org/publickey.asc > _______________________________________________ > CentOS-virt mailing list > CentOS-virt(a)centos.org > http://lists.centos.org/mailman/listinfo/centos-virt > _______________________________________________ CentOS-virt mailing list CentOS-virt(a)centos.org http://lists.centos.org/mailman/listinfo/centos-virt

1 0

Seeing dropped packets / tcp retrans on latest 4.4.1-10el6
by Nathan March 20 Apr '15

20 Apr '15

Hi All, Was troubleshooting some odd VM network issues and discovered that we're seeing dropped packets + retransmissions across multiple domU OS's and dom0 hardware platforms. xendev01 ~ # tshark -R "tcp.analysis.retransmission " -i vif7.0 Running as user "root" and group "root". This could be dangerous. Capturing on vif7.0 3.054257 xxx.xxx.xxx.196 -> xxx.xxx.xxx.145 SSH 110 [TCP Fast Retransmission] Encrypted response packet len=44 3.061949 xxx.xxx.xxx.196 -> xxx.xxx.xxx.145 SSH 1434 [TCP Fast Retransmission] Encrypted response packet len=1368 3.383880 xxx.xxx.xxx.196 -> xxx.xxx.xxx.145 SSH 1434 [TCP Fast Retransmission] Encrypted response packet len=1368 3.630911 xxx.xxx.xxx.196 -> xxx.xxx.xxx.145 SSH 1434 [TCP Fast Retransmission] Encrypted response packet len=1368 3.635964 xxx.xxx.xxx.196 -> xxx.xxx.xxx.145 SSH 1434 [TCP Fast Retransmission] Encrypted response packet len=1368 I've confirmed this is happening with linux, windows and pfsense (bsd) domU's. I've turned off every feature I can with ethtool on both the underlying bridge on the host, the vif's, and the eth's inside the domU's. I also see it on traffic inbetween vms on the same host. The domU sees packet errors on incoming traffic and outgoing looks fine, dumping on the dom0 indicates incoming packets are fine, but the reply from the domU is broken. This does not happen running the exact same VMs on some older xen 4.1.3 hosts. Reproduction is easy (for me at least), any burst of traffic will do it. I've just been running "ps auxf" over ssh to a vm to trigger. Since I'm seeing it on the host when I sniff the vif, this feels like a bug? - Nathan

2 4

CBS Tag Hierarchy
by Sandro Bonazzola 20 Apr '15

20 Apr '15

Hi, please review CBS Tag Hierarchy proposed / implemented by alphacc on https://bugs.centos.org/view.php?id=8407 for aligning Virt SIG to the other SIGs. Looks ok to me. Thanks, -- Sandro Bonazzola Better technology. Faster innovation. Powered by community collaboration. See how it works at redhat.com

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