Hello everyone,
I would like to ask for your feedback about tuning the official CentOS images for Vagrant. The good news: the next release will probably provide Vagrant images for both CentOS 6 and 7, not just 7 as until now.
Deltarpm allows yum to download just binary diffs for the already installed packages and rebuild the rpms locally, thus decreasing the used bandwidth. However, this is quite CPU and I/O intensive, and significantly slower than just downloading the full packages (at least for users on any sort of broadband connection). Deltarpm can be useful for users in development countries, which do not always have access to unmetered broadband, while someone hosting many VM instances on the same server, like a VPS provider, might want to avoid the extra I/O load (especially on mechanical hard-disks). Deltarpm is already part of the CentOS 7 images since May 2015 - should we keep it or remove it?
Tuned, a daemon that can adjust system parameters based on the workload (it comes with a number of profiles, optimized for different situations), is preinstalled in CentOS 7, and can significantly improve performance and/or reduce load. Tuned can also be installed in CentOS 6, and it would increase the size of the Vagrant image with just 291kB, since its prerequisites are already installed. Should we add it to CentOS 6? If you are not familiar with tuned, the following links might be helpful:
http://servicesblog.redhat.com/2012/04/16/tuning-your-system-with-tuned/ http://www.slideshare.net/IamFedora/tuned
Thanks in advance, Laurențiu
I'd suggest keeping centos6 looking like vanilla centos6 to the extent possible, rather than adding things not native to that base os as it comes from upstream.....
Re: deltarpm, again I'd have centos7 run like vanilla unaltered centos7 to the extent possible. If it uses deltarpm, so be it.
Once you go down the path of over-optimizing for one or a few user communities, you'll be signing up for a lot of labor and questions regarding 'why does my vagrant box not work like a baremetal centosNNN box?' type questions. Danger.....
-- Vince Skahan Infrastructure Engineering and Support Office of Research Information Services (ORIS)
-----Original Message----- From: centos-devel-bounces@centos.org [mailto:centos-devel-bounces@centos.org] On Behalf Of Laurentiu Pancescu Sent: Tuesday, April 26, 2016 6:56 AM To: The CentOS developers mailing list. centos-devel@centos.org Subject: [CentOS-devel] RFC: Performance tuning of the Vagrant images
Hello everyone,
I would like to ask for your feedback about tuning the official CentOS images for Vagrant. The good news: the next release will probably provide Vagrant images for both CentOS 6 and 7, not just 7 as until now.
Deltarpm allows yum to download just binary diffs for the already installed packages and rebuild the rpms locally, thus decreasing the used bandwidth. However, this is quite CPU and I/O intensive, and significantly slower than just downloading the full packages (at least for users on any sort of broadband connection). Deltarpm can be useful for users in development countries, which do not always have access to unmetered broadband, while someone hosting many VM instances on the same server, like a VPS provider, might want to avoid the extra I/O load (especially on mechanical hard-disks). Deltarpm is already part of the CentOS 7 images since May 2015 - should we keep it or remove it?
Tuned, a daemon that can adjust system parameters based on the workload (it comes with a number of profiles, optimized for different situations), is preinstalled in CentOS 7, and can significantly improve performance and/or reduce load. Tuned can also be installed in CentOS 6, and it would increase the size of the Vagrant image with just 291kB, since its prerequisites are already installed. Should we add it to CentOS 6? If you are not familiar with tuned, the following links might be helpful:
http://servicesblog.redhat.com/2012/04/16/tuning-your-system-with-tuned/ http://www.slideshare.net/IamFedora/tuned
Thanks in advance, Laurențiu _______________________________________________ CentOS-devel mailing list CentOS-devel@centos.org https://lists.centos.org/mailman/listinfo/centos-devel
Hello Vince,
thanks for the feedback. I also prefer minimalism, and not changing defaults without a good reason.
On Tue, Apr 26, 2016 at 7:42 PM, Vince Skahan vds@uw.edu wrote:
I'd suggest keeping centos6 looking like vanilla centos6 to the extent possible, rather than adding things not native to that base os as it comes from upstream.....
The package selection depends on what you select during install. I think deltarpm isn't installed by a minimal install, but it might be on desktops (I never installed a CentOS desktop, but Fedora Workstation includes deltarpm, while Fedora Cloud doesn't, if I remeber correctly). That's not an issue, though, since deltarpm doesn't bring any functional differences, from a user's perspective: "yum update" produces identical results (and the admin can force yum to not use diff packages via yum.conf - all these variants are officially supported and documented). Both deltarpm and tuned make a lot of sense for a system that only runs as a VM guest, to minimize the impact on the host, and they are transparent to the user. The tuned profiles are the result of optimization work done by RedHat over many months, and fully supported and documented upstream - see the Power Management Guide, for both version 6 and 7.
However, some other things in our Vagrant images *do* bring functional differences. The firewall is disabled, and we add rsync and nfs-utils to the image, since they provide things that Vagrant, or some of its plugins, need. bash-completion is also added on CentOS 7 (not part of @base). And we create a smaller swap partition than recommended by RedHat's installation guide, to conserve space.
Once you go down the path of over-optimizing for one or a few user communities, you'll be signing up for a lot of labor and questions regarding 'why does my vagrant box not work like a baremetal centosNNN box?' type questions. Danger.....
The Vagrant images are only intended for Vagrant users, running under one of the supported virtualization solutions. I think it makes sense to adapt them to run as smoothly as possible for their special use case: as a VM guest. But you're right, we need to document any changes, so people know what to expect.
Best regards, Laurențiu
I didn't realize from your original email that tuned was available in centos6 as just-another-rpm. Sorry for the confusion.
Incidentally when you're doing the vagrant images, can you please create the CD/DVD device in your base boxes ? That's a pain to have to continually add/fix via the Vagrantfile after the fact, and it's needed to follow the usual interactive ways to install the vagrant guest additions documented on the Vagrant website (although yes, it can be done other ways too).
-- Vince Skahan Infrastructure Engineering and Support Office of Research Information Services (ORIS)
On 4/27/16 6:44 PM, Vince Skahan wrote:
I didn't realize from your original email that tuned was available in centos6 as just-another-rpm. Sorry for the confusion.
No problem. I also misunderstood your position as opposing any change to the default configuration, even if appropriate for the purpose of the images. :)
Incidentally when you're doing the vagrant images, can you please create the CD/DVD device in your base boxes ? That's a pain to have to continually add/fix via the Vagrantfile after the fact, and it's needed to follow the usual interactive ways to install the vagrant guest additions documented on the Vagrant website (although yes, it can be done other ways too).
I wouldn't risk such a change now, with the release just a few days away. This is something we'll have to look at next month, after the release.
Best regards, Laurențiu
On 26/04/16 14:55, Laurentiu Pancescu wrote:
Hello everyone,
I would like to ask for your feedback about tuning the official CentOS images for Vagrant. The good news: the next release will probably provide Vagrant images for both CentOS 6 and 7, not just 7 as until now.
Deltarpm allows yum to download just binary diffs for the already installed packages and rebuild the rpms locally, thus decreasing the used bandwidth. However, this is quite CPU and I/O intensive, and significantly slower than just downloading the full packages (at least for users on any sort of broadband connection). Deltarpm can be useful for users in development countries, which do not always have access to unmetered broadband, while someone hosting many VM instances on the same server, like a VPS provider, might want to avoid the extra I/O load (especially on mechanical hard-disks). Deltarpm is already part of the CentOS 7 images since May 2015 - should we keep it or remove it?
Tuned, a daemon that can adjust system parameters based on the workload (it comes with a number of profiles, optimized for different situations), is preinstalled in CentOS 7, and can significantly improve performance and/or reduce load. Tuned can also be installed in CentOS 6, and it would increase the size of the Vagrant image with just 291kB, since its prerequisites are already installed. Should we add it to CentOS 6?
yes, lets add tuned to the c6 image, it can make a huge impact. And I believe there was consideration to add it to all CentOS-6 images including the cloud and centos userland ones.
w.r.t deltarpm, I'd say skip it for now, we can make add a README to the image root that tells people they can install it. and we can then retospectively decide if its a good win ( based on user feedback ).
On CentOS-7, lets leave tuned and deltarpm in for now, since we've already set some user expectations around it.
Hello Karanbir,
On 4/27/16 10:29 AM, Karanbir Singh wrote:
yes, lets add tuned to the c6 image, it can make a huge impact. And I believe there was consideration to add it to all CentOS-6 images including the cloud and centos userland ones.
Done, I sent you a pull request on GitHub.
w.r.t deltarpm, I'd say skip it for now, we can make add a README to the image root that tells people they can install it. and we can then retospectively decide if its a good win ( based on user feedback ).
I performed a test, as an attempt to measure the impact of deltarpm. Please see my comment on PR #44:
https://github.com/CentOS/sig-cloud-instance-build/pull/44#issuecomment-2151...
On CentOS-7, lets leave tuned and deltarpm in for now, since we've already set some user expectations around it.
Okay.
Best regards, Laurențiu
-
Karanbir Singh -
Laurentiu Pancescu -
Vince Skahan