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very low performance of Xen guests
by Manuel Wolfshant 16 Jun '20

16 Jun '20

Hello For the past months I've been testing upgrading my Xen hosts to CentOS 7 and I face an issue for which I need your help to solve. The testing machines are IBM blades, model H21 and H21XM. Initial tests were performed on the H21 with 16 GB RAM; during the last 6=7 weeks I've been using the H21XM with 64 GB. In all cases the guests were fully updated CentOS 7 -- initially 7.6 ( most recent at the time of the initial tests ), and respectively 7.8 for the tests performed during the last 2 months. As host I used initially CentOS 6 with latest kernel available in the centos virt repo at the time of the tests and CentOS 7 with the latest kernel as well. As xen versions I tested 4.8 and 4.12 ( xl info included below ). The storage for the last tests is a Crucial MX500 but results were similar when using traditional HDD. My problem, in short, is that the guests are extremely slow. For instance , in the most recent tests, a yum install kernel takes cca 1 min on the host and 12-15 (!!!) minutes in the guest, all time being spent in dracut regenerating the initramfs images. I've done rough tests with the storage ( via dd if=/dev/zero of=a_test_file size bs=10M count=1000 ) and the speed was comparable between the hosts and the guests. The version of the kernel in use inside the guest also did not seem to make any difference . OTOH, sysbench ( https://github.com/akopytov/sysbench/ ) as well as p7zip benchmark report for the guests a speed which is between 10% and 50% of the host. Quite obviously, changing the elevator had no influence either. Here is the info which I think that should be relevant for the software versions in use. Feel free to ask for any additional info. [root@t7 ~]# xl info host : t7 release : 4.9.215-36.el7.x86_64 version : #1 SMP Mon Mar 2 11:42:52 UTC 2020 machine : x86_64 nr_cpus : 8 max_cpu_id : 7 nr_nodes : 1 cores_per_socket : 4 threads_per_core : 1 cpu_mhz : 3000.122 hw_caps : bfebfbff:000ce3bd:20100800:00000001:00000000:00000000:00000000:00000000 virt_caps : pv hvm total_memory : 57343 free_memory : 53620 sharing_freed_memory : 0 sharing_used_memory : 0 outstanding_claims : 0 free_cpus : 0 xen_major : 4 xen_minor : 12 xen_extra : .2.39.g3536f8dc xen_version : 4.12.2.39.g3536f8dc xen_caps : xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32 hvm-3.0-x86_32p hvm-3.0-x86_64 xen_scheduler : credit2 xen_pagesize : 4096 platform_params : virt_start=0xffff800000000000 xen_changeset : xen_commandline : placeholder dom0_mem=1024M,max:1024M cpuinfo com1=115200,8n1 console=com1,tty loglvl=all guest_loglvl=all ucode=-1 cc_compiler : gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-39) cc_compile_by : mockbuild cc_compile_domain : centos.org cc_compile_date : Tue Apr 14 14:22:04 UTC 2020 build_id : 24148a191438467f26a9e16089205544a428f661 xend_config_format : 4 [root@t5 ~]# xl info host : t5 release : 4.9.215-36.el6.x86_64 version : #1 SMP Mon Mar 2 10:30:40 UTC 2020 machine : x86_64 nr_cpus : 8 max_cpu_id : 7 nr_nodes : 1 cores_per_socket : 4 threads_per_core : 1 cpu_mhz : 2000 hw_caps : b7ebfbff:0004e33d:20100800:00000001:00000000:00000000:00000000:00000000 virt_caps : hvm total_memory : 12287 free_memory : 6955 sharing_freed_memory : 0 sharing_used_memory : 0 outstanding_claims : 0 free_cpus : 0 xen_major : 4 xen_minor : 8 xen_extra : .5.86.g8db85532 xen_version : 4.8.5.86.g8db85532 xen_caps : xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32 hvm-3.0-x86_32p hvm-3.0-x86_64 xen_scheduler : credit xen_pagesize : 4096 platform_params : virt_start=0xffff800000000000 xen_changeset : xen_commandline : dom0_mem=1024M,max:1024M cpuinfo com1=115200,8n1 console=com1,tty loglvl=all guest_loglvl=all cc_compiler : gcc (GCC) 4.4.7 20120313 (Red Hat 4.4.7-23) cc_compile_by : mockbuild cc_compile_domain : centos.org cc_compile_date : Thu Dec 12 14:34:48 UTC 2019 build_id : da34ae5b90c82137dcbc466cd66322381bc6fd21 xend_config_format : 4 /Note:/ with all other kernels and xen versions that were published for C6 during the last year, the performance was the same, i.e. slow The test VM is exactly the same, copied among servers: [root@t7 ~]# cat /etc/xen/test7_1 builder = "hvm" xen_platform_pci=1 name = "Test7" memory = 2048 maxmem = 4096 vcpus = 2 vif = [ "mac=00:14:5e:d9:df:50,bridge=xenbr0,model=e1000" ] disk = [ "file:/var/lib/xen/images/test7_1,xvda,w" ] sdl = 0 vnc = 1 bootloader = 'xenpvnetboot' #bootloader_args = ['--location', 'http://internal.x.y/mrepo/centos7-x86_64/disc1/'] on_poweroff = 'destroy' on_reboot = 'restart' on_crash = 'restart' #boot="nd" boot="d" pae=1 acpi=1 apic=1 tsc_mode=0 /Notes:/ - the lines past "boot" in the config do not make any difference either, they were added during the last week's tests. - I've tested with 1, 2, 4 and 8 VCPUs . There is no diff for the real life apps. Frankly in this moment I have no idea what else to change or test so .. please help.

3 4

Amazon Machine Image failing because of ec2:RunInstances Not authorized for images: [ami-03c4e540f2256d223]
by Jay Wisniewski 09 Jun '20

09 Jun '20

Hi, Not sure why, but when trying to create an instance the build fails with not being able to access marketplace image. API: ec2:RunInstances Not authorized for images: [ami-03c4e540f2256d223] Currently subscribed to the CENTOS 7 AMI with updates. >From Amazon: This ami-03c4e540f2256d223 may be depreciated by the provider if it is not letting you to launch new instances from it, means it is no longer available. You would need to find the latest AMI version from the marketplace on the page where you begin configuration or I would suggest contact the marketplace provider support directly, unfortunately we do not have insight in those images, only the provider. This way they'll update the below mappings in the CloudFormation template with the relevant AMI for us-west-2 region for you. --- "AWSRegionArch2AMI": { "us-east-1": { "HVM64": "ami-0e683f9e59dd2838c" }, "us-west-2": { "HVM64": "ami-03c4e540f2256d223" }, "us-west-1": { "HVM64": "ami-08eaa393abc9e7ee2" Please advise. Jay Wisniewski Systems Administrator Information Technology

1 0

Centos 8 on AWS
by Thomas Stephen Lee 14 May '20

14 May '20

Hi, Please release CentOS 8 on AWS. reference https://bugs.centos.org/view.php?id=16614#c36929 Also, a query: Is there any cost (money) for releasing on AWS by organizations? thanks --- Lee

1 0

VM migration problems
by isdtor 25 Apr '20

25 Apr '20

I have migrated KVM VMs from a CentOS 6 to a CentOS 7 host. All work fine post-migration, CentOS 3 (don't ask ...), CentOS 6, CentOS 7, Windows. But the CentOS 5 VMs failed. At some point during the boot process, they became unpingable and also inaccessible. I have correlated this to the start of the irqbalance service and was wondering if it is generally considered best practice to turn it off. The VMs in question all have at least 2 vcpus, and the C5 VMs are the odd ones out.

3 4

ANNOUNCE: centos-release-xen to switch to newer xen
by Anthony PERARD 14 Apr '20

14 Apr '20

Greeting, We are about to update the centos-release-xen package to point to a newer version of Xen. That is 4.12 on CentOS 7 but only 4.10 on CentOS 6. As a reminder, you can "pin" your installation to Xen 4.8 by installing centos-release-xen-48 and then removing centos-release-xen. Other available Xen version are: centos-release-xen-48 centos-release-xen-410 centos-release-xen-412 (CentOS 7 only) On CentOS 6, ocaml is too old to build some component of Xen 4.12. There may be other issues. (I'll wait at least two weeks before pushing from testing to the release repo.) Cheers, -- Anthony PERARD

1 1

virt module
by Tane Adam 16 Mar '20

16 Mar '20

Hi. I am attempting to modify the virt module and rebuild it. Wondering if anyone here can provide some guidance on how to do that. I found the instructions here about locally building modules. https://docs.fedoraproject.org/en-US/modularity/making-modules/building-mod… A couple problems: * the virt module is not hosted on src.fedoraproject.org/ * module-build-system does not appear to be readily available Questions: * What is the process to rebuild a module on CentOS? * Are the sources for the virt module closed source (RH)? Or is it available somewhere? Thanks in advance. Tane.

1 0

Question about latest CentOS 7 AWS AMI
by Edward Mossman 08 Mar '20

08 Mar '20

Hi, I'm seeing some strange behavior when trying to use the latest CentOS 7 AMI from the AWS marketplace. The AMI that we've been using previously is "ami-02eac2c0129f6376b" released January 30, 2019 at 6:40:58 PM Today I saw a new AMI with ID "ami-0c3b960f8440c7d71" that was released February 21, 2020 at 3:50:07 Both these AMIs are owned by AWS account 679593333241. Before I was able to use the latest AMI released February 21, I was prompted to subscribe to new marketplace terms and conditions. The link that I received was an AWS marketplace page owned by a vendor named "Supported Images" that seemed highly suspicious. My questions are: 1. Did CentOS release an AWS AMI on February 21? 2. Has anything about the distribution of official CentOS AWS AMIs changed? 3. Is there a better channel for me to speak with someone involved in the release process that might know more? Thank you, Edward Mossman -- [image: Cloudreach] <https://hubs.ly/H09D_X50> *Edward Mossman* Cloud Systems Developer Tech Lead +1 646 799 1311 <+1+646+799+1311> | +1 212 335 0700 | www.cloudreach.com 1095 Ave of the Americas – 14th Floor, 3 Bryant Park, New York, NY 10036 USA [image: LinkedIn] <https://hubs.ly/H09sS3c0> [image: Twitter] <https://hubs.ly/H09sS520> [image: Facebook] <https://hubs.ly/H09sSjy0> [image: Glassdoor] <https://hubs.ly/H09sS7b0> [image: Instagram] <https://www.instagram.com/lifeatcloudreach/> Cloudreach named in Gartner's Magic Quadrant for Managed Services <https://www.gartner.com/doc/reprints?id=1-6APMXIX&ct=190301&st=sb> -- The above terms reflect a potential business arrangement, are provided solely as a basis for further discussion, and are not intended to be and do not constitute a legally binding obligation. No legally binding obligations will be created, implied, or inferred until an agreement in final form is executed in writing by all parties involved. This email may be confidential or privileged. If you received this communication by mistake, please don't forward it to anyone else, please erase all copies and attachments, and please let us know that it has gone to the wrong person. Cloudreach Inc. is registered in Delaware, with the registered office at 1679 S. DuPont Highway, Suite 100, Dover, Kent, DE 19901 and registration number 5427661.

2 1

xen hvm domU and > 3 nic's... bug?
by Christoph 27 Feb '20

27 Feb '20

Hi I cant start a hvm domU with more than 3 nic's configured... why? it is a bug? With previous versions it was possible... here the config - it is an opnsense (openbsd) hvm domU: name = "fenrir.chao5.int" uuid = "7aedcd03-54e8-4055-8d1b-37dd34194859" maxmem = 2048 memory = 2048 loader = '/usr/lib64/xen/boot/hvmloader' type = "hvm" vcpus = 2 rtc_timeoffset = 0 localtime = 1 on_poweroff = "destroy" on_reboot = "restart" on_crash = "restart" vnc = 1 vncunused = 0 vncdisplay = 100 vnclisten = "0.0.0.0" keymap = "de" vif = [ "mac=00:16:3e:05:30:04,bridge=xenbr5,script=vif-bridge,model=e1000", "mac=00:16:3e:04:30:04,bridge=xenbr4,script=vif-bridge,model=e1000", "mac=00:16:3e:15:30:04,bridge=xenbr15,script=vif-bridge,model=e1000", "mac=00:16:3e:14:30:04,bridge=xenbr14,script=vif-bridge,model=e1000" ] parallel = "none" serial = "none" disk = [ "phy:/dev/vg_lamia/lv_fenrir_root,hda,rw", "phy:/dev/vg_lamia/lv_fenrir_swap,hdb,rw" ] pci_power_mgmt=1 xen_platform_pci=1 pci_msitranslate=1 viridian=0 hpet=1 acpi=1 apic=1 pae=1 pvh=1 with 3 nic's it does work... -- ------ Greetz

2 2

pvh domU and pvgrub with grub2
by Christoph 27 Feb '20

27 Feb '20

Hi it is meanwhile possible to use pvgrub/grub2 inside a pvh domU? -- ------ Greetz

1 0

pvh domU and pvgrub with grub2
by Christoph 25 Feb '20

25 Feb '20

Hi it is meanwhile possible to use pvgrub/grub2 inside a pvh domU? -- ------ Greetz

1 0

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