On Wed, Jul 31, 2019 at 8:07 PM Dumitru Ceara <[email protected]> wrote:
> On Mon, Jul 29, 2019 at 7:43 PM <[email protected]> wrote: > > > > From: Numan Siddique <[email protected]> > > > > This patch adds 3 unixctl socket comments - pause, resume and is-paused. > > > > Usage: ovs-appctl -t ovn-northd pause/resume/is-paused > > > > This feature will be useful if the CMS wants to > > - deploy OVN DB servers in active/passive mode and > > - run ovn-northd on all these nodes and use unix ctl sockets to > > connect to the local OVN DB servers. > > > > On the nodes where OVN Db ovsdb-servers are in passive mode, the local > ovn-northds > > will process the DB changes and compute logical flows to be thrown out > later, > > because write transactions are not allowed by these ovsdb-servers. It > results in > > unncessary CPU usage. > > > > With these commands, CMS can pause ovn-northd on these node. A node > > which becomes master, can resume the ovn-northd. > > > > One use case is to use this feature in ovn-kubernetes with the above > deployment model. > > > > Acked-by: Mark Michelson <[email protected]> > > Signed-off-by: Numan Siddique <[email protected]> > > --- > > > > v3 -> v4 > > ======== > > * Submitted the patch for the OVN repo > > > > v2 -> v3 > > ======= > > * Resolved merge conflicts. > > > > v1 -> v2 > > ======= > > * Addressed the review comments from Ben and add more documentation > > about the runtime options added by this patch. > > * v1 had an issue - When paused, it was not even waking up to process > > the IDL updates. In v2, the main thread, wakes up to process any > > IDL updates, but doesn't do any logical flow computations. > > > > northd/ovn-northd.8.xml | 48 ++++++++++++++++ > > northd/ovn-northd.c | 121 ++++++++++++++++++++++++++++++---------- > > tests/ovn-northd.at | 38 +++++++++++++ > > 3 files changed, 179 insertions(+), 28 deletions(-) > > > > diff --git a/northd/ovn-northd.8.xml b/northd/ovn-northd.8.xml > > index d2267de0e..1d0243656 100644 > > --- a/northd/ovn-northd.8.xml > > +++ b/northd/ovn-northd.8.xml > > @@ -70,6 +70,23 @@ > > <dd> > > Causes <code>ovn-northd</code> to gracefully terminate. > > </dd> > > + > > + <dt><code>pause</code></dt> > > + <dd> > > + Pauses the ovn-northd operation from processing any Northbound > and > > + Southbound database changes. > > + </dd> > > + > > + <dt><code>resume</code></dt> > > + <dd> > > + Resumes the ovn-northd operation to process Northbound and > > + Southbound database contents and generate logical flows. > > + </dd> > > + > > + <dt><code>is-paused</code></dt> > > + <dd> > > + Returns "true" if ovn-northd is currently paused, "false" > otherwise. > > + </dd> > > </dl> > > </p> > > > > @@ -82,6 +99,37 @@ > > of <code>ovn-northd</code> will automatically take over. > > </p> > > > > + <h2> Active-Standby with multiple OVN DB servers</h2> > > + <p> > > + You may run multiple OVN DB servers in an OVN deployment with: > > + <ul> > > + <li> > > + OVN DB servers deployed in active/passive mode with one active > > + and multiple passive ovsdb-servers. > > + </li> > > + > > + <li> > > + <code>ovn-northd</code> also deployed on all these nodes, > > + using unix ctl sockets to connect to the local OVN DB servers. > > + </li> > > + </ul> > > + </p> > > + > > + <p> > > + In such deployments, the ovn-northds on the passive nodes will > process > > + the DB changes and compute logical flows to be thrown out later, > > + because write transactions are not allowed by the passive > ovsdb-servers. > > + It results in unnecessary CPU usage. > > + </p> > > + > > + <p> > > + With the help of runtime management command <code>pause</code>, > you can > > + pause <code>ovn-northd</code> on these nodes. When a passive node > > + becomes master, you can use the runtime management command > > + <code>resume</code> to resume the <code>ovn-northd</code> to > process the > > + DB changes. > > + </p> > > + > > <h1>Logical Flow Table Structure</h1> > > > > <p> > > diff --git a/northd/ovn-northd.c b/northd/ovn-northd.c > > index bed2993c2..fcb19b8a1 100644 > > --- a/northd/ovn-northd.c > > +++ b/northd/ovn-northd.c > > @@ -52,6 +52,9 @@ > > VLOG_DEFINE_THIS_MODULE(ovn_northd); > > > > static unixctl_cb_func ovn_northd_exit; > > +static unixctl_cb_func ovn_northd_pause; > > +static unixctl_cb_func ovn_northd_resume; > > +static unixctl_cb_func ovn_northd_is_paused; > > > > struct northd_context { > > struct ovsdb_idl *ovnnb_idl; > > @@ -9182,6 +9185,7 @@ main(int argc, char *argv[]) > > struct unixctl_server *unixctl; > > int retval; > > bool exiting; > > + bool paused; > > > > fatal_ignore_sigpipe(); > > ovs_cmdl_proctitle_init(argc, argv); > > @@ -9196,6 +9200,10 @@ main(int argc, char *argv[]) > > exit(EXIT_FAILURE); > > } > > unixctl_command_register("exit", "", 0, 0, ovn_northd_exit, > &exiting); > > + unixctl_command_register("pause", "", 0, 0, ovn_northd_pause, > &paused); > > + unixctl_command_register("resume", "", 0, 0, ovn_northd_resume, > &paused); > > + unixctl_command_register("is-paused", "", 0, 0, > ovn_northd_is_paused, > > + &paused); > > > > daemonize_complete(); > > > > @@ -9384,34 +9392,51 @@ main(int argc, char *argv[]) > > > > /* Main loop. */ > > exiting = false; > > + paused = false; > > while (!exiting) { > > - struct northd_context ctx = { > > - .ovnnb_idl = ovnnb_idl_loop.idl, > > - .ovnnb_txn = ovsdb_idl_loop_run(&ovnnb_idl_loop), > > - .ovnsb_idl = ovnsb_idl_loop.idl, > > - .ovnsb_txn = ovsdb_idl_loop_run(&ovnsb_idl_loop), > > - .sbrec_ha_chassis_grp_by_name = > sbrec_ha_chassis_grp_by_name, > > - .sbrec_mcast_group_by_name_dp = > sbrec_mcast_group_by_name_dp, > > - .sbrec_ip_mcast_by_dp = sbrec_ip_mcast_by_dp, > > - }; > > - > > - if (!had_lock && ovsdb_idl_has_lock(ovnsb_idl_loop.idl)) { > > - VLOG_INFO("ovn-northd lock acquired. " > > - "This ovn-northd instance is now active."); > > - had_lock = true; > > - } else if (had_lock && !ovsdb_idl_has_lock(ovnsb_idl_loop.idl)) > { > > - VLOG_INFO("ovn-northd lock lost. " > > - "This ovn-northd instance is now on standby."); > > - had_lock = false; > > - } > > - > > - if (ovsdb_idl_has_lock(ovnsb_idl_loop.idl)) { > > - ovn_db_run(&ctx, sbrec_chassis_by_name, &ovnsb_idl_loop); > > - if (ctx.ovnsb_txn) { > > - check_and_add_supported_dhcp_opts_to_sb_db(&ctx); > > - check_and_add_supported_dhcpv6_opts_to_sb_db(&ctx); > > - check_and_update_rbac(&ctx); > > + /* unixctl_server_run could modify the value of 'paused'. > > + * So store the value in local 'paused_' so that we run > > + * 'ovsdb_idl_loop_commit_and_wait() at the end of the loop. */ > > + bool paused_ = paused; > > + > > + if (!paused_) { > > + struct northd_context ctx = { > > + .ovnnb_idl = ovnnb_idl_loop.idl, > > + .ovnnb_txn = ovsdb_idl_loop_run(&ovnnb_idl_loop), > > + .ovnsb_idl = ovnsb_idl_loop.idl, > > + .ovnsb_txn = ovsdb_idl_loop_run(&ovnsb_idl_loop), > > + .sbrec_ha_chassis_grp_by_name = > sbrec_ha_chassis_grp_by_name, > > + .sbrec_mcast_group_by_name_dp = > sbrec_mcast_group_by_name_dp, > > + .sbrec_ip_mcast_by_dp = sbrec_ip_mcast_by_dp, > > + }; > > + > > + if (!had_lock && ovsdb_idl_has_lock(ovnsb_idl_loop.idl)) { > > + VLOG_INFO("ovn-northd lock acquired. " > > + "This ovn-northd instance is now active."); > > + had_lock = true; > > + } else if (had_lock && > !ovsdb_idl_has_lock(ovnsb_idl_loop.idl)) { > > + VLOG_INFO("ovn-northd lock lost. " > > + "This ovn-northd instance is now on standby."); > > + had_lock = false; > > } > > + > > + if (ovsdb_idl_has_lock(ovnsb_idl_loop.idl)) { > > + ovn_db_run(&ctx, sbrec_chassis_by_name, > &ovnsb_idl_loop); > > + if (ctx.ovnsb_txn) { > > + check_and_add_supported_dhcp_opts_to_sb_db(&ctx); > > + check_and_add_supported_dhcpv6_opts_to_sb_db(&ctx); > > + check_and_update_rbac(&ctx); > > + } > > + } > > + } else { > > + /* ovn-northd is paused > > + * - we still want to handle any db updates and update > the > > + * local IDL. Otherwise, when it is resumed, the local > IDL > > + * copy will be out of sync. > > + * - but we don't want to create any txns. > > + * */ > > + ovsdb_idl_run(ovnnb_idl_loop.idl); > > + ovsdb_idl_run(ovnsb_idl_loop.idl); > > } > > > > unixctl_server_run(unixctl); > > @@ -9419,8 +9444,16 @@ main(int argc, char *argv[]) > > if (exiting) { > > poll_immediate_wake(); > > } > > - ovsdb_idl_loop_commit_and_wait(&ovnnb_idl_loop); > > - ovsdb_idl_loop_commit_and_wait(&ovnsb_idl_loop); > > + > > + if (!paused_) { > > + ovsdb_idl_loop_commit_and_wait(&ovnnb_idl_loop); > > + ovsdb_idl_loop_commit_and_wait(&ovnsb_idl_loop); > > + } else { > > + /* ovn-northd is paused, but we still want to wake up for > any db > > + * updates. */ > > + ovsdb_idl_wait(ovnnb_idl_loop.idl); > > + ovsdb_idl_wait(ovnsb_idl_loop.idl); > > + } > > > > poll_block(); > > Hi Numan, > > I think that if we reorder a bit the operations and execute the > "unixctl_server_run/wait" calls and check for "exiting" just before > poll_block() then there's no need to have the local paused_ and we can > avoid having two "if(paused)". > Thanks for the suggestion. I will do that and submit v5. Thanks Numan > > Cheers, > Dumitru > > > if (should_service_stop()) { > > @@ -9445,3 +9478,35 @@ ovn_northd_exit(struct unixctl_conn *conn, int > argc OVS_UNUSED, > > > > unixctl_command_reply(conn, NULL); > > } > > + > > +static void > > +ovn_northd_pause(struct unixctl_conn *conn, int argc OVS_UNUSED, > > + const char *argv[] OVS_UNUSED, void *pause_) > > +{ > > + bool *pause = pause_; > > + *pause = true; > > + > > + unixctl_command_reply(conn, NULL); > > +} > > + > > +static void > > +ovn_northd_resume(struct unixctl_conn *conn, int argc OVS_UNUSED, > > + const char *argv[] OVS_UNUSED, void *pause_) > > +{ > > + bool *pause = pause_; > > + *pause = false; > > + > > + unixctl_command_reply(conn, NULL); > > +} > > + > > +static void > > +ovn_northd_is_paused(struct unixctl_conn *conn, int argc OVS_UNUSED, > > + const char *argv[] OVS_UNUSED, void *paused_) > > +{ > > + bool *paused = paused_; > > + if (*paused) { > > + unixctl_command_reply(conn, "true"); > > + } else { > > + unixctl_command_reply(conn, "false"); > > + } > > +} > > diff --git a/tests/ovn-northd.at b/tests/ovn-northd.at > > index 62e58fd0e..0dea04edc 100644 > > --- a/tests/ovn-northd.at > > +++ b/tests/ovn-northd.at > > @@ -898,3 +898,41 @@ as northd > > OVS_APP_EXIT_AND_WAIT([ovn-northd]) > > > > AT_CLEANUP > > + > > +AT_SETUP([ovn -- ovn-northd pause and resume]) > > +AT_SKIP_IF([test $HAVE_PYTHON = no]) > > +ovn_start > > + > > +AT_CHECK([test xfalse = x`as northd ovs-appctl -t ovn-northd > is-paused`]) > > + > > +ovn-nbctl ls-add sw0 > > + > > +OVS_WAIT_UNTIL([ > > + ovn-sbctl lflow-list sw0 > > + test 0 = $?]) > > + > > +ovn-nbctl ls-del sw0 > > +OVS_WAIT_UNTIL([ > > + ovn-sbctl lflow-list sw0 > > + test 1 = $?]) > > + > > +# Now pause the ovn-northd > > +as northd ovs-appctl -t ovn-northd pause > > +AT_CHECK([test xtrue = x`as northd ovs-appctl -t ovn-northd is-paused`]) > > + > > +ovn-nbctl ls-add sw0 > > + > > +# There should be no logical flows for sw0 datapath. > > +OVS_WAIT_UNTIL([ > > + ovn-sbctl lflow-list sw0 > > + test 1 = $?]) > > + > > +# Now resume ovn-northd > > +as northd ovs-appctl -t ovn-northd resume > > +AT_CHECK([test xfalse = x`as northd ovs-appctl -t ovn-northd > is-paused`]) > > + > > +OVS_WAIT_UNTIL([ > > + ovn-sbctl lflow-list sw0 > > + test 0 = $?]) > > + > > +AT_CLEANUP > > -- > > 2.21.0 > > > > _______________________________________________ > > dev mailing list > > [email protected] > > https://mail.openvswitch.org/mailman/listinfo/ovs-dev > _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
