virt January 2013

virt@lists.centos.org

28 participants
19 discussions

Package lists for Cloud images
by Karanbir Singh 01 Jun '13

01 Jun '13

hi Guys, As we get ready to start publishing Cloud Images ( or rather images consumable in various virt platforms, including public and private clouds ) - it would be great to have a baseline package manifest worked out. What / how many images should we build. At this time we were thinking of doing : - CentOS-5 32bit minimal - CentOS-6 32bit minimal - CentOS-5 64bit minimal - CentOS-6 64bit minimal - CentOS-5 64bit LAMP - CentOS-6 64bit LAMP What would be the minimal functional requirements people would expect from these images ? and what rpms should be installed ? Should root login be enabled or should we require people to go in via a 'centos' user. Should the image be self-updating, or should we have a post-login message that indicates outstanding updates ? -- Karanbir Singh +44-207-0999389 | http://www.karan.org/ | twitter.com/kbsingh ICQ: 2522219 | Yahoo IM: z00dax | Gtalk: z00dax GnuPG Key : http://www.karan.org/publickey.asc

12 37

Re: [CentOS-virt] Time
by James B. Byrne 17 Feb '13

17 Feb '13

On Wed, January 2, 2013 12:51, SilverTip257 wrote: > On Wed, Jan 2, 2013 at 9:41 AM, James B. Byrne > <byrnejb(a)harte-lyne.ca>wrote: > >> >> I ran into this situation several times whilst testing KVM and the >> lessons I learned from the experiences can be summarized as: >> >> 1. Never allow the kvm hypervisior to handle guests during a host >> shutdown. Use 'virsh shutdown' on each of the guests first and then >> shutdown the host. Use autostart to restart guests on a host's >> reboot. Write a script to process 'virsh list' to feed active >> domains >> to 'virsh shutdown' if automation is required and link that to >> /etc/rc0.d/K10<whatever>. >> >> > @James: Can you specifically cite why you manually power down each > node? Have you tried tweaking your libvirt settings in the config > file I noted in my earlier response to Robert? Two reasons. First, I am minimally familiar with kvm. The niceties of the options for it is beyond my kin for the nonce. Second, libvirt does not always work. I have had guests refuse to either suspend or shutdown from an automatic request to do so. When shutdown is done manually one discovers right away that there is a problem and which guest is causing it. > Set up a central NTP server and have your hosts (and not just VMs) > connect to it. It could be the VM host, but doesn't need to be. > Distribute the load to your NTP server and off of the public NTP pool > by running an NTP server for your servers to poll [0] ... it's a good > practice and everybody is happy. > I do that as well. However, I run one on each host just to serve its own guests and configure the host to run off our central ntp server. > > >> 4. On each guest have a cron job that checks for ntpd at regular >> intervals which reports failures and restarts the time service as >> necessary. We use: >> JOBNAME="Check ntpd status and restart if required" ; \ >> ntpstat > /dev/null && \ >> if [[ $? -gt 0 ]]; then /sbin/service ntpd start; fi >> >> > Why not configure the ntpd daemon and stick with that? > It does update on its own [1]. And ntpstat prints out the interval, > which matches the one mentioned at [1]. > I don't believe the ntpstat script/job is necessary (I've never had to > do more than set ntpd to run after configuring the servers it should > poll). > You misunderstand the purpose of the job. Netstat checks to see if the daemon is actually running. If it is not then netstat returns a non-zero exit code. If the ntpstat exit code is not zero then the service script is invoked to restart it. Additionally, netstat writes out to stderr that it could not find the daemon which gets emailed to support. I probably should have used [[ ! $? -eq 0 ]] but what I have written does work. We found ntpd just stoped on some guests upon occasion without any visible trace of a cause. Not frequently but when it did happen it was a nuisance to detect before clock drift on the guest caused some failure or other. This job detects these occurrences and self corrects. These are all CentOS-6.3 hosts and guests. -- *** E-Mail is NOT a SECURE channel *** 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

5 4

cloud-init in CentOS 6.3 images
by Brian Lalor 08 Feb '13

08 Feb '13

Good evening, all. I just tried spinning up a CentOS instance in EC2 using ami-de5bd2ee from the AWS marketplace. I put a dummy script into the user-data field when launching the instance from the EC2 console but found it didn't work, even though the SSH key for the root user did. I pinged Karanbir on ##aws and he suggested I post here to get the conversation started. I'm currently looking into what it takes to roll my own AMI; I've already invested a fair bit of work into creating packages and Puppet config based on a CentOS 6.3 system (mainly with Vagrant), and my initial test with Amazon's Linux AMI wasn't promising. I think execution of the user-data script is a must-have, as it's the only way to automate the creation of a new instance without external tools. Thanks, Brian

3 4

domU doesn't see all memory
by sg＠cyon.ch 24 Jan '13

24 Jan '13

Hi, I'm running CentOS 6.2 x86_64 as xen guest on a CentOS 5.7 dom0. The host is running 2.6.18-274.7.1.el5xen, the guest 2.6.32-220.2.1.el6.x86_64. Memory for domU is set to 1024 MB and "xm list" shows these 1024 MB. But "free -m" on the guest system shows only 652 MB. When I set up a CentOS 5.x guest with 1024 MB "free -m" shoes 1024 MB. Anyone else seeing this? Any ideas on how to fix it? Cheers, Sebastian

7 8

virt-manager
by mattias 23 Jan '13

23 Jan '13

are there any windows based software to administer an kvm hhost? e.g create edit machines no web based

6 7

Upgrading libvirt and qemu to latest version
by Peter Smith 20 Jan '13

20 Jan '13

Hi, I am considering upgrading the libvirt to v0.10.1 and qemu-kvm to v1.2 qemu version because they are recommended by Ceph. I am wondering does CentOS kernel support upstream qemu well? And are there rpms for theses version somewhere? or I have to build myself? Thanks. Peter

2 1

i solved it
by mattias 18 Jan '13

18 Jan '13

cool i now administer my kvm host from my laptop with virt-manager now i should only figure out how to asign public ips

3 2

virt-manager
by mattias 17 Jan '13

17 Jan '13

can i connect to a libvirt-host over internet? it work with ssh but with tcp?

3 2

create a guest
by mattias 16 Jan '13

16 Jan '13

can i create a guest with libvirt and use an existing disc with freebsd?

4 7

create a guest
by mattias 16 Jan '13

16 Jan '13

can i create a guest with libvirt and use an existing disc with freebsd?

3 4

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virt January 2013