witness.wiki

   1 <[sambabg]
   2
   3 ==== ====[plain]
   4
   5 <[center]
   6 \Large
   7 '''Outlook: clustering / witness'''
   8 [center]>
   9
  10 [frame]>
  11 [sambabg]>
  12
  13 ==== Witness - General ====
  14
  15 * New DCE/RPC Service to “witness” availability of IPs, shares, ...
  16 * ==> Faster fail-over of clients in the cluster
  17 * Prompt, explicit, and controlled notifications about failures \ %
  18   (CTDB tickle-ACKs are implicit)
  19 * Available since SMB3 (Windows 8 / Windows Server 2012)
  20
  21 ==== Witness - Failover with SMB3 in a Samba/CTDB cluster ====
  22
  23 -<1>{
  24 <[center]
  25 <<<design-ctdb-three-nodes-with-witness-step0.png, width=.95\textwidth>>>
  26 [center]>
  27 }
  28
  29 -<2>{
  30 <[center]
  31 <<<design-ctdb-three-nodes-with-witness-step1.png, width=.95\textwidth>>>
  32 [center]>
  33 }
  34
  35 -<3>{
  36 <[center]
  37 <<<design-ctdb-three-nodes-with-witness-step2a.png, width=.95\textwidth>>>
  38 [center]>
  39 }
  40
  41 -<4>{
  42 <[center]
  43 <<<design-ctdb-three-nodes-with-witness-step2b.png, width=.95\textwidth>>>
  44 [center]>
  45 }
  46
  47 -<5>{
  48 <[center]
  49 <<<design-ctdb-three-nodes-with-witness-step3a.png, width=.95\textwidth>>>
  50 [center]>
  51 }
  52
  53 -<6>{
  54 <[center]
  55 <<<design-ctdb-three-nodes-with-witness-step3b.png, width=.95\textwidth>>>
  56 [center]>
  57 }
  58
  59 -<7>{
  60 <[center]
  61 <<<design-ctdb-three-nodes-with-witness-step4.png, width=.95\textwidth>>>
  62 [center]>
  63 }
  64
  65 -<8>{
  66 <[center]
  67 <<<design-ctdb-three-nodes-with-witness-step5.png, width=.95\textwidth>>>
  68 [center]>
  69 }
  70
  71 ==== Witness - Samba ====
  72
  73 <[block]{Currently under development in Samba}
  74 * PoC implementation available
  75 * TODO(wip): new _red_async_ DCE/RPC infrastructure
  76 * {\footnotesize @https://wiki.samba.org/index.php/Samba3/ \\ %
  77    SMB2\#Witness\_Notification\_Protocol@}
  78 * WIP branch: \\ %
  79   {\footnotesize @https://git.samba.org/?p=gd/samba/.git;a=shortlog; \\ %
  80    h=refs/heads/master-witness@}
  81 [block]>
  82
  83 <[block]{Samba Witness service will cause Windows clients to reconnect...}
  84 * when client admin tool is used
  85 * when CTDB (or any other cluster resource control manager) moves resources or IP addresses
  86 [block]>
  87
  88 [frame]>
  89