README

   1 KERNEL SOURCE:
   2 ==============
   3
   4 We currently use the Ubuntu kernel sources, available from our mirror:
   5
   6  https://git.proxmox.com/?p=mirror_ubuntu-kernels.git;a=summary
   7
   8 Ubuntu will maintain those kernels till:
   9
  10  https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
  11  or
  12  https://pve.proxmox.com/pve-docs/chapter-pve-faq.html#faq-support-table
  13
  14  whatever happens to be earlier.
  15
  16
  17 Additional/Updated Modules:
  18 ---------------------------
  19
  20 - include native OpenZFS filesystem kernel modules for Linux
  21
  22   * https://github.com/zfsonlinux/
  23
  24   For licensing questions, see: http://open-zfs.org/wiki/Talk:FAQ
  25
  26
  27 SUBMODULE
  28 =========
  29
  30 We track the current upstream repository as submodule. Besides obvious
  31 advantages over tracking binary tar archives this also has some implications.
  32
  33 For building the submodule directory gets copied into build/ and a few patches
  34 get applied with the `patch` tool. From a git point-of-view, the copied
  35 directory remains clean even with extra patches applied since it does not
  36 contain a .git directory, but a reference to the (still pristine) submodule:
  37
  38 $ cat build/ubuntu-kernel/.git
  39
  40 If you mistakenly cloned the upstream repo as "normal" clone (not via the
  41 submodule mechanics) this means that you have a real .git directory with its
  42 independent objects and tracking info when copying for building, thus git
  43 operates on the copied directory - and "sees" that it was dirtied by `patch`,
  44 and thus the kernel buildsystem sees this too and will add a '+' to the version
  45 as a result. This changes the output directories for modules and other build
  46 artefacts and let's then the build fail on packaging.
  47
  48 So always ensure that you really checked it out as submodule, not as full
  49 "normal" clone. You can also explicitly set the LOCALVERSION variable to
  50 undefined with: `export LOCALVERSION= but that should only be done for test
  51 builds.
  52
  53 RELATED PACKAGES:
  54 =================
  55
  56 proxmox-ve
  57 ----------
  58
  59 top level meta package, depends on current default kernel series meta package.
  60
  61 git clone git://git.proxmox.com/git/proxmox-ve.git
  62
  63 pve-kernel-meta
  64 ---------------
  65
  66 Depends on latest kernel and header package within a certain kernel series,
  67 e.g., pve-kernel-5.15 / pve-headers-5.15
  68
  69 git clone git://git.proxmox.com/git/pve-kernel-meta.git
  70
  71 pve-firmware
  72 ------------
  73
  74 Contains the firmware for all released PVE kernels.
  75
  76 git clone git://git.proxmox.com/git/pve-firmware.git
  77
  78
  79 NOTES:
  80 ======
  81
  82 ABI versions, package versions and package name:
  83 ------------------------------------------------
  84
  85 We follow debian's versioning w.r.t ABI changes:
  86
  87 https://kernel-team.pages.debian.net/kernel-handbook/ch-versions.html
  88 https://wiki.debian.org/DebianKernelABIChanges
  89
  90 The debian/rules file has a target comparing the build kernel's ABI against the
  91 version stored in the repository and indicates when an ABI bump is necessary.
  92 An ABI bump within one upstream version consists of incrementing the KREL
  93 variable in the Makefile, rebuilding the packages and running 'make abiupdate'
  94 (the 'abiupdate' target in 'Makefile' contains the steps for consistently
  95 updating the repository).
  96
  97 Watchdog blacklist
  98 ------------------
  99
 100 By default, all watchdog modules are black-listed because it is totally undefined
 101 which device is actually used for /dev/watchdog.
 102 We ship this list in /lib/modprobe.d/blacklist_pve-kernel-<VERSION>.conf
 103 The user typically edit /etc/modules to enable a specific watchdog device.
 104
 105 Debug kernel and modules
 106 ------------------------
 107
 108 In order to build a -dbgsym package containing an unstripped copy of the kernel
 109 image and modules, enable the 'pkg.pve-kernel.debug' build profile (e.g. by
 110 exporting DEB_BUILD_PROFILES='pkg.pve-kernel.debug'). The resulting package can
 111 be used together with 'crash'/'kdump-tools' to debug kernel crashes.
 112
 113 Note: the -dbgsym package is only valid for the pve-kernel packages produced by
 114 the same build. A kernel/module from a different build will likely not match,
 115 even if both builds are of the same kernel and package version.
 116
 117 Additional information
 118 ----------------------
 119
 120 We use the default configuration provided by Ubuntu, and apply
 121 the following modifications:
 122
 123 NOTE: For the exact and current list see debian/rules (PVE_CONFIG_OPTS)
 124
 125 - enable INTEL_MEI_WDT=m (to allow disabling via patch)
 126
 127 - disable CONFIG_SND_PCM_OSS (enabled by default in Ubuntu, not needed)
 128
 129 - switch CONFIG_TRANSPARENT_HUGEPAGE to MADVISE from ALWAYS
 130
 131 - enable CONFIG_CEPH_FS=m (request from user)
 132
 133 - enable common CONFIG_BLK_DEV_XXX to avoid hardware detection
 134   problems (udev, update-initramfs have serious problems without that)
 135
 136          CONFIG_BLK_DEV_SD=y
 137          CONFIG_BLK_DEV_SR=y
 138          CONFIG_BLK_DEV_DM=y
 139
 140 - compile NBD and RBD modules
 141          CONFIG_BLK_DEV_NBD=m
 142          CONFIG_BLK_DEV_RBD=m
 143
 144 - enable IBM JFS file system as module
 145   requested by users (bug #64)
 146
 147 - enable apple HFS and HFSPLUS as module
 148   requested by users
 149
 150 - enable CONFIG_BCACHE=m (requested by user)
 151
 152 - enable CONFIG_BRIDGE=y
 153   to avoid warnings on boot, e.g. that net.bridge.bridge-nf-call-iptables is an unknown key
 154
 155 - enable CONFIG_DEFAULT_SECURITY_APPARMOR
 156   We need this for lxc
 157
 158 - set CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE=y
 159   because if not set, it can give some dynamic memory or cpu frequencies
 160   change, and vms can crash (mainly windows guest).
 161   see http://forum.proxmox.com/threads/18238-Windows-7-x64-VMs-crashing-randomly-during-process-termination?p=93273#post93273
 162
 163 - use 'deadline' as default scheduler
 164   This is the suggested setting for KVM. We also measure bad fsync performance with ext4 and cfq.
 165
 166 - disable CONFIG_INPUT_EVBUG
 167   Module evbug is not blacklisted on debian, so we simply disable it to avoid
 168   key-event logs (which is a big security problem)
 169
 170 - enable CONFIG_MODVERSIONS (needed for ABI tracking)
 171
 172 - switch default UNWINDER to FRAME_POINTER
 173   the recently introduced ORC_UNWINDER is not 100% stable yet, especially in combination with ZFS
 174
 175 - enable CONFIG_PAGE_TABLE_ISOLATION (Meltdown mitigation)