Documentation/faq/releases.rst

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   2       Licensed under the Apache License, Version 2.0 (the "License"); you may
   3       not use this file except in compliance with the License. You may obtain
   4       a copy of the License at
   5
   6           http://www.apache.org/licenses/LICENSE-2.0
   7
   8       Unless required by applicable law or agreed to in writing, software
   9       distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  10       WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  11       License for the specific language governing permissions and limitations
  12       under the License.
  13
  14       Convention for heading levels in Open vSwitch documentation:
  15
  16       =======  Heading 0 (reserved for the title in a document)
  17       -------  Heading 1
  18       ~~~~~~~  Heading 2
  19       +++++++  Heading 3
  20       '''''''  Heading 4
  21
  22       Avoid deeper levels because they do not render well.
  23
  24 ========
  25 Releases
  26 ========
  27
  28 Q: What does it mean for an Open vSwitch release to be LTS (long-term support)?
  29
  30     A: All official releases have been through a comprehensive testing process
  31     and are suitable for production use.  Planned releases occur twice a year.
  32     If a significant bug is identified in an LTS release, we will provide an
  33     updated release that includes the fix.  Releases that are not LTS may not
  34     be fixed and may just be supplanted by the next major release.  The current
  35     LTS release is 2.5.x.
  36
  37     For more information on the Open vSwitch release process, refer to
  38     :doc:`/internals/release-process`.
  39
  40 Q: What Linux kernel versions does each Open vSwitch release work with?
  41
  42     A: The following table lists the Linux kernel versions against which the
  43     given versions of the Open vSwitch kernel module will successfully build.
  44     The Linux kernel versions are upstream kernel versions, so Linux kernels
  45     modified from the upstream sources may not build in some cases even if they
  46     are based on a supported version.  This is most notably true of Red Hat
  47     Enterprise Linux (RHEL) kernels, which are extensively modified from
  48     upstream.
  49
  50     ============ ==============
  51     Open vSwitch Linux kernel
  52     ============ ==============
  53     1.4.x        2.6.18 to 3.2
  54     1.5.x        2.6.18 to 3.2
  55     1.6.x        2.6.18 to 3.2
  56     1.7.x        2.6.18 to 3.3
  57     1.8.x        2.6.18 to 3.4
  58     1.9.x        2.6.18 to 3.8
  59     1.10.x       2.6.18 to 3.8
  60     1.11.x       2.6.18 to 3.8
  61     2.0.x        2.6.32 to 3.10
  62     2.1.x        2.6.32 to 3.11
  63     2.3.x        2.6.32 to 3.14
  64     2.4.x        2.6.32 to 4.0
  65     2.5.x        2.6.32 to 4.3
  66     2.6.x        3.10 to 4.7
  67     2.7.x        3.10 to 4.9
  68     2.8.x        3.10 to 4.12
  69     2.9.x        3.10 to 4.13
  70     2.10.x       3.16 to 4.17
  71     2.11.x       3.16 to 4.18
  72     2.12.x       3.16 to 5.0
  73     2.14.x       3.16 to 5.5
  74     ============ ==============
  75
  76     Open vSwitch userspace should also work with the Linux kernel module built
  77     into Linux 3.3 and later.
  78
  79     Open vSwitch userspace is not sensitive to the Linux kernel version.  It
  80     should build against almost any kernel, certainly against 2.6.32 and later.
  81
  82     Open vSwitch branches 2.10 through 2.14 will still compile against the
  83     RHEL and CentOS 7 3.10 based kernels since they have diverged from the
  84     Linux kernel.org 3.10 kernels.
  85
  86 Q: Are all features available with all datapaths?
  87
  88     A: Open vSwitch supports different datapaths on different platforms.  Each
  89     datapath has a different feature set: the following tables try to summarize
  90     the status.
  91
  92     Supported datapaths:
  93
  94     Linux upstream
  95       The datapath implemented by the kernel module shipped with Linux
  96       upstream.  Since features have been gradually introduced into the kernel,
  97       the table mentions the first Linux release whose OVS module supports the
  98       feature.
  99
 100     Linux OVS tree
 101       The datapath implemented by the Linux kernel module distributed with the
 102       OVS source tree.
 103
 104     Userspace
 105       This datapath supports conventional system devices as well as
 106       DPDK and AF_XDP devices when support for those is built.  This
 107       is the only datapath that works on NetBSD, FreeBSD and Mac OSX.
 108
 109     Hyper-V
 110       Also known as the Windows datapath.
 111
 112     The following table lists the datapath supported features from an
 113     Open vSwitch user's perspective.  The "Linux upstream" column
 114     lists the Linux kernel version that introduced a given feature
 115     into its kernel module.  The "Linux OVS tree" and "Userspace"
 116     columns list the Open vSwitch release versions that introduced a
 117     given feature into the included kernel module or the userspace
 118     datapath, respectively.
 119
 120     ========================== ============== ============== ========= =======
 121     Feature                    Linux upstream Linux OVS tree Userspace Hyper-V
 122     ========================== ============== ============== ========= =======
 123     Connection tracking             4.3            2.5          2.6      YES
 124     Conntrack Fragment Reass.       4.3            2.6          2.12     YES
 125     Conntrack Timeout Policies      5.2            2.12         2.14     NO
 126     Conntrack Zone Limit            4.18           2.10         2.13     YES
 127     Conntrack NAT                   4.6            2.6          2.8      YES
 128     Tunnel - LISP                   NO             2.11         NO       NO
 129     Tunnel - STT                    NO             2.4          NO       YES
 130     Tunnel - GRE                    3.11           1.0          2.4      YES
 131     Tunnel - VXLAN                  3.12           1.10         2.4      YES
 132     Tunnel - Geneve                 3.18           2.4          2.4      YES
 133     Tunnel - GRE-IPv6               4.18           2.6          2.6      NO
 134     Tunnel - VXLAN-IPv6             4.3            2.6          2.6      NO
 135     Tunnel - Geneve-IPv6            4.4            2.6          2.6      NO
 136     Tunnel - ERSPAN                 4.18           2.10         2.10     NO
 137     Tunnel - ERSPAN-IPv6            4.18           2.10         2.10     NO
 138     Tunnel - GTP-U                  NO             NO           2.14     NO
 139     QoS - Policing                  YES            1.1          2.6      NO
 140     QoS - Shaping                   YES            1.1          NO       NO
 141     sFlow                           YES            1.0          1.0      NO
 142     IPFIX                           3.10           1.11         1.11     YES
 143     Set action                      YES            1.0          1.0    PARTIAL
 144     NIC Bonding                     YES            1.0          1.0      YES
 145     Multiple VTEPs                  YES            1.10         1.10     YES
 146     Meter action                    4.15           2.10         2.7      NO
 147     check_pkt_len action            5.2            2.12         2.12     NO
 148     ========================== ============== ============== ========= =======
 149
 150     Do note, however:
 151
 152     * Only a limited set of flow fields is modifiable via the set action by the
 153       Hyper-V datapath.
 154
 155     * Userspace datapath support, in some cases, is dependent on the associated
 156       interface types.  For example, DPDK interfaces support ingress and egress
 157       policing, but not shaping.
 158
 159     The following table lists features that do not *directly* impact an Open
 160     vSwitch user, e.g. because their absence can be hidden by the ofproto layer
 161     (usually this comes with a performance penalty).
 162
 163     ===================== ============== ============== ========= =======
 164     Feature               Linux upstream Linux OVS tree Userspace Hyper-V
 165     ===================== ============== ============== ========= =======
 166     SCTP flows            3.12           YES            YES       YES
 167     MPLS                  3.19           YES            YES       YES
 168     UFID                  4.0            YES            YES       NO
 169     Megaflows             3.12           YES            YES       NO
 170     Masked set action     4.0            YES            YES       NO
 171     Recirculation         3.19           YES            YES       YES
 172     TCP flags matching    3.13           YES            YES       NO
 173     Validate flow actions YES            YES            N/A       NO
 174     Multiple datapaths    YES            YES            YES       NO
 175     Tunnel TSO - STT      N/A            YES            NO        YES
 176     ===================== ============== ============== ========= =======
 177
 178 Q: What DPDK version does each Open vSwitch release work with?
 179
 180     A: The following table lists the DPDK version against which the given
 181     versions of Open vSwitch will successfully build.
 182
 183     ============ =======
 184     Open vSwitch DPDK
 185     ============ =======
 186     2.2.x        1.6
 187     2.3.x        1.6
 188     2.4.x        2.0
 189     2.5.x        2.2
 190     2.6.x        16.07.2
 191     2.7.x        16.11.9
 192     2.8.x        17.05.2
 193     2.9.x        17.11.4
 194     2.10.x       17.11.4
 195     2.11.x       18.11.6
 196     2.12.x       18.11.6
 197     2.13.x       19.11.0
 198     ============ =======
 199
 200 Q: Are all the DPDK releases that OVS versions work with maintained?
 201
 202     No. DPDK follows YY.MM.n (Year.Month.Number) versioning.
 203
 204     Typically, all DPDK releases get a stable YY.MM.1 update with bugfixes 3
 205     months after the YY.MM.0 release. In some cases there may also be a
 206     YY.MM.2 release.
 207
 208     DPDK LTS releases start once a year at YY.11.0 and are maintained for
 209     two years, with YY.MM.n+1 releases around every 3 months.
 210
 211     The latest information about DPDK stable and LTS releases can be found
 212     at `DPDK stable`_.
 213
 214 .. _DPDK stable: http://dpdk.org/doc/guides/contributing/stable.html
 215
 216 Q: I get an error like this when I configure Open vSwitch:
 217
 218         configure: error: Linux kernel in <dir> is version <x>, but
 219         version newer than <y> is not supported (please refer to the
 220         FAQ for advice)
 221
 222     What should I do?
 223
 224     A: You have the following options:
 225
 226     - Use the Linux kernel module supplied with the kernel that you are using.
 227       (See also the following FAQ.)
 228
 229     - If there is a newer released version of Open vSwitch, consider building
 230       that one, because it may support the kernel that you are building
 231       against.  (To find out, consult the table in the previous FAQ.)
 232
 233     - The Open vSwitch "master" branch may support the kernel that you are
 234       using, so consider building the kernel module from "master".
 235
 236     All versions of Open vSwitch userspace are compatible with all versions of
 237     the Open vSwitch kernel module, so you do not have to use the kernel module
 238     from one source along with the userspace programs from the same source.
 239
 240 Q: What features are not available in the Open vSwitch kernel datapath that
 241 ships as part of the upstream Linux kernel?
 242
 243     A: The kernel module in upstream Linux does not include support for LISP.
 244     Work is in progress to add support for LISP to the upstream Linux version
 245     of the Open vSwitch kernel module. For now, if you need this feature, use
 246     the kernel module from the Open vSwitch distribution instead of the
 247     upstream Linux kernel module.
 248
 249     Certain features require kernel support to function or to have reasonable
 250     performance. If the ovs-vswitchd log file indicates that a feature is not
 251     supported, consider upgrading to a newer upstream Linux release or using
 252     the kernel module paired with the userspace distribution.
 253
 254 Q: Why do tunnels not work when using a kernel module other than the one
 255 packaged with Open vSwitch?
 256
 257     A: Support for tunnels was added to the upstream Linux kernel module after
 258     the rest of Open vSwitch. As a result, some kernels may contain support for
 259     Open vSwitch but not tunnels. The minimum kernel version that supports each
 260     tunnel protocol is:
 261
 262     ======== ============
 263     Protocol Linux Kernel
 264     ======== ============
 265     GRE      3.11
 266     VXLAN    3.12
 267     Geneve   3.18
 268     ERSPAN   4.18
 269     LISP     not upstream
 270     STT      not upstream
 271     ======== ============
 272
 273     If you are using a version of the kernel that is older than the one listed
 274     above, it is still possible to use that tunnel protocol. However, you must
 275     compile and install the kernel module included with the Open vSwitch
 276     distribution rather than the one on your machine. If problems persist after
 277     doing this, check to make sure that the module that is loaded is the one
 278     you expect.
 279
 280 Q: Why are UDP tunnel checksums not computed for VXLAN or Geneve?
 281
 282     A: Generating outer UDP checksums requires kernel support that was not part
 283     of the initial implementation of these protocols. If using the upstream
 284     Linux Open vSwitch module, you must use kernel 4.0 or newer. The
 285     out-of-tree modules from Open vSwitch release 2.4 and later support UDP
 286     checksums.
 287
 288 Q: What features are not available when using the userspace datapath?
 289
 290     A: Tunnel virtual ports are not supported, as described in the previous
 291     answer.  It is also not possible to use queue-related actions.  On Linux
 292     kernels before 2.6.39, maximum-sized VLAN packets may not be transmitted.
 293
 294 Q: Should userspace or kernel be upgraded first to minimize downtime?
 295
 296     A. In general, the Open vSwitch userspace should be used with the kernel
 297     version included in the same release or with the version from upstream
 298     Linux.  However, when upgrading between two releases of Open vSwitch it is
 299     best to migrate userspace first to reduce the possibility of
 300     incompatibilities.
 301
 302 Q: What happened to the bridge compatibility feature?
 303
 304     A: Bridge compatibility was a feature of Open vSwitch 1.9 and earlier.
 305     When it was enabled, Open vSwitch imitated the interface of the Linux
 306     kernel "bridge" module.  This allowed users to drop Open vSwitch into
 307     environments designed to use the Linux kernel bridge module without
 308     adapting the environment to use Open vSwitch.
 309
 310     Open vSwitch 1.10 and later do not support bridge compatibility.  The
 311     feature was dropped because version 1.10 adopted a new internal
 312     architecture that made bridge compatibility difficult to maintain.  Now
 313     that many environments use OVS directly, it would be rarely useful in any
 314     case.
 315
 316     To use bridge compatibility, install OVS 1.9 or earlier, including the
 317     accompanying kernel modules (both the main and bridge compatibility
 318     modules), following the instructions that come with the release.  Be sure
 319     to start the ovs-brcompatd daemon.