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For anyone who does not know what PXE (pixie) boot is, it is an environment to boot computers using a network interface independently of data storage devices (l
by WestCoastJustin 13y ago
For anyone who does not know what PXE (pixie) boot is, it is an environment to boot computers using a network interface independently of data storage devices (like hard disks) or installed operating systems. [1] In the BIOS, rather than booting from CD, or Hard disk, you would select Network.
A very simplified explanation is that the PXE enabled network card (almost all modern network cards support PXE, desktop and servers), can make a DHCP request (outside of an operating system), download via TFTP, then boot a kernel/initial ram disk, say for example an OS installer, a LIVE CD, or CoreOS.
+-----> #1 PXE makes DHCP request,
| redirects to TFTP server,
| loads kernel/initial ram disk via TFTP
|
| +--+ #2 PXE boots kernel/initial ram disk
| |
+ v
+------------------+
| PXE Network Card |
|------------------|
| server |
| hardware/os |
+------------------+
So, with a little infrastructure (DHCP, TFTP, and elbow grease), you can boot many things over the network without even having a hard drive or cd-rom in a machine. I use this often for installing new desktops and servers. Just boot into the PXE menu and then select the installer that I want. Then you use something like puppet to configure the machine as needed. A typical RHEL install can take ~5 minutes.
In summary, it looks like CoreOS provides you with their kernel and initial ram disk [2], then you can just boot the machine over the network without actually installing anything. Basically running everything out of RAM, just like a LIVE CD, most likely with the option to install to disk for persistent storage of your images, etc.
ps. It is common to use NFS to mount persistent storage in these environments too, or if you are using a HPC environment, then Luster or something like that.
[1] http://en.wikipedia.org/wiki/Preboot_Execution_Environment http://en.wikipedia.org/wiki/Preboot_Execution_Environment
[2] http://coreos.com/docs/pxe/ http://coreos.com/docs/pxe/
- ewams 13y agoIt is possible to PXE boot a full blown OS, not just OS installer, Live CD or CoreOS. The product usually used to do this is: http://support.citrix.com/proddocs/topic/technologies/pvs-provisioning.html http://support.citrix.com/proddocs/topic/technologies/pvs-pr... It is just a nice GUI that ties into PXE and TFTP and just streams an image from a disk file. On a 1Gb network I have booted over 300 physical machines in under 2 minutes simultaneously. For those curious, unfortunately PVS is packaged with XenDesktop so you have to buy XenDesktop to get PVS. Citrix does not seem willing to separate the two as different products even though I have deployed PVS for several customers without even download the XenDestkop bits.
- devicenull 13y agoDRBL can do this for Linux (if you require some software to set it up for you). You can actually accomplish this with nothing more then the linux kernel if you're clever: https://www.kernel.org/doc/Documentation/filesystems/nfs/nfsroot.txt https://www.kernel.org/doc/Documentation/filesystems/nfs/nfs...
- deleted 13y ago[deleted]
- ewams 13y agoThanks I have not heard of DRBL. After reading it sounds pretty much like PVS, though PVS does have some additional features I don't see on it. Will have to try it out! DRBL is a free software though.
- justincormack 13y agoThe product usually used to do this is Linux...
- ewams 13y agoYea I meant "I usually" :-p
- deleted 13y ago[deleted]
- jlgaddis 13y ago"Back in the day" (pre-PXE), we had rooms full of machines -- without hard drives -- that booted completely across the network and mounted all of their filesystems via NFS. https://en.wikipedia.org/wiki/Diskless_node https://en.wikipedia.org/wiki/Diskless_node Over the last few years, I've wondered why server vendors don't ship servers with type of flash-based storage (or similar) -- perhaps 4-8 GB -- that's large enough to hold an installation of (for example) VMware ESXi (or another hypervisor) and its related configuration files, leaving any local storage exclusively for VMs. Alternatively, you could boot the hypervisor from this "onboard storage" and access all data across the network (i.e. NFS, iSCSI, SAN) and not have any HDDs whatsoever in the server.
- telephonetemp 13y agoWell, there's the solution of putting a USB flash drive inside the server's case (optionally securing it with duct tape). In fact, a USB flash drive is the recommend medium for booting FreeNAS.
- enigmo 13y agoI've been looking at a mSATA SSD and a low profile pcie card for our Ceph cluster to free up the OS/journal drive slots for more 4tb spinning disks.
- tacticus 13y agoHow are you finding ceph?
- rajahafify 13y agoCan bios detect wireless network or do i need to have Ethernet cable on?
- nitrogen 13y agoThere might be some motherboards with built-in WiFi chips that support PXE with configurable access point and security settings. Maybe try a Duck Duck Go search for wifi PXE. There's no way for the BIOS to know your WPA key automatically, of course, and in general, you'll need wired Ethernet for PXE.