ctdb/config/statd-callout

   1 #!/bin/sh
   2
   3 # This must run as root as CTDB tool commands need to access CTDB socket
   4 [ $(id -u) -eq 0 ] || exec sudo "$0" "$@"
   5
   6 # this script needs to be installed so that statd points to it with the -H
   7 # command line argument. The easiest way to do that is to put something like this in
   8 # /etc/sysconfig/nfs:
   9 #   STATD_HOSTNAME="myhostname -H /etc/ctdb/statd-callout"
  10
  11 [ -n "$CTDB_BASE" ] || \
  12     export CTDB_BASE=$(cd -P $(dirname "$0") ; echo "$PWD")
  13
  14 . $CTDB_BASE/functions
  15
  16 # Overwrite this so we get some logging
  17 die ()
  18 {
  19     script_log "statd-callout" "$@"
  20     exit 1
  21 }
  22
  23 loadconfig ctdb
  24 loadconfig nfs
  25
  26 [ -n "$NFS_HOSTNAME" ] || \
  27     die "NFS_HOSTNAME is not configured. statd-callout failed"
  28
  29 # A handy newline
  30 nl="
  31 "
  32
  33 ctdb_setup_service_state_dir "statd-callout"
  34
  35 cd "$service_state_dir" || \
  36     die "Failed to change directory to \"${service_state_dir}\""
  37
  38 case "$1" in
  39     # Keep a single file to keep track of the last "add-client" or
  40     # "del-client'.  These get pushed to ctdb.tdb during "update",
  41     # which will generally be run once each "monitor" cycle.  In this
  42     # way we avoid scalability problems with flood of persistent
  43     # transactions after a "notify" when all the clients re-take their
  44     # locks.
  45
  46     add-client)
  47         # statd does not tell us to which IP the client connected so
  48         # we must add it to all the IPs that we serve
  49         cip="$2"
  50         ctdb_get_pnn
  51         date=$(date '+%s')
  52         ctdb ip -X |
  53         tail -n +2 |
  54         while IFS="|" read x sip node x ; do
  55             [ "$node" = "$pnn" ] || continue # not us
  56             key="statd-state@${sip}@${cip}"
  57             echo "\"${key}\" \"${date}\"" >"$key"
  58         done
  59         ;;
  60
  61     del-client)
  62         # statd does not tell us from which IP the client disconnected
  63         # so we must add it to all the IPs that we serve
  64         cip="$2"
  65         ctdb_get_pnn
  66         ctdb ip -X |
  67         tail -n +2 |
  68         while IFS="|" read x sip node x ; do
  69             [ "$node" = "$pnn" ] || continue # not us
  70             key="statd-state@${sip}@${cip}"
  71             echo "\"${key}\" \"\"" >"$key"
  72         done
  73         ;;
  74
  75     update)
  76         files=$(echo statd-state@*)
  77         if [ "$files" = "statd-state@*" ] ; then
  78             # No files!
  79             exit 0
  80         fi
  81         # Filter out lines for any IP addresses that are not currently
  82         # hosted public IP addresses.
  83         ctdb_get_pnn
  84         ctdb_ips=$(ctdb ip | tail -n +2)
  85         sed_expr=$(echo "$ctdb_ips" |
  86             awk -v pnn=$pnn 'pnn == $2 { \
  87                 ip = $1; gsub(/\./, "\\.", ip); \
  88                 printf "/statd-state@%s@/p\n", ip }')
  89         if cat $files | sed -n "$sed_expr" | ctdb ptrans "ctdb.tdb" ; then
  90             rm $files
  91         fi
  92         ;;
  93
  94     notify)
  95         # we must restart the lockmanager (on all nodes) so that we get
  96         # a clusterwide grace period (so other clients don't take out
  97         # conflicting locks through other nodes before all locks have been
  98         # reclaimed)
  99
 100         # we need these settings to make sure that no tcp connections survive
 101         # across a very fast failover/failback
 102         #echo 10 > /proc/sys/net/ipv4/tcp_fin_timeout
 103         #echo 0 > /proc/sys/net/ipv4/tcp_max_tw_buckets
 104         #echo 0 > /proc/sys/net/ipv4/tcp_max_orphans
 105
 106         # Delete the notification list for statd, we don't want it to
 107         # ping any clients
 108         rm -f /var/lib/nfs/statd/sm/*
 109         rm -f /var/lib/nfs/statd/sm.bak/*
 110
 111         # we must keep a monotonically increasing state variable for the entire
 112         # cluster  so state always increases when ip addresses fail from one
 113         # node to another
 114         # We use epoch and hope the nodes are close enough in clock.
 115         # Even numbers mean service is shut down, odd numbers mean
 116         # service is started.
 117         state_even=$(( $(date '+%s') / 2 * 2))
 118
 119         # We must also let some time pass between stopping and
 120         # restarting the lock manager.  Otherwise there is a window
 121         # where the lock manager will respond "strangely" immediately
 122         # after restarting it, which causes clients to fail to reclaim
 123         # their locks.
 124         "$CTDB_NFS_CALLOUT" "stop" "nlockmgr" >/dev/null 2>&1
 125         sleep 2
 126         "$CTDB_NFS_CALLOUT" "start" "nlockmgr" >/dev/null 2>&1
 127
 128         # we now need to send out additional statd notifications to ensure
 129         # that clients understand that the lockmanager has restarted.
 130         # we have three cases:
 131         # 1, clients that ignore the ip address the stat notification came from
 132         #    and ONLY care about the 'name' in the notify packet.
 133         #    these clients ONLY work with lock failover IFF that name
 134         #    can be resolved into an ipaddress that matches the one used
 135         #    to mount the share.  (==linux clients)
 136         #    This is handled when starting lockmanager above,  but those
 137         #    packets are sent from the "wrong" ip address, something linux
 138         #    clients are ok with, buth other clients will barf at.
 139         # 2, Some clients only accept statd packets IFF they come from the
 140         #    'correct' ip address.
 141         # 2a,Send out the notification using the 'correct' ip address and also
 142         #    specify the 'correct' hostname in the statd packet.
 143         #    Some clients require both the correct source address and also the
 144         #    correct name. (these clients also ONLY work if the ip addresses
 145         #    used to map the share can be resolved into the name returned in
 146         #    the notify packet.)
 147         # 2b,Other clients require that the source ip address of the notify
 148         #    packet matches the ip address used to take out the lock.
 149         #    I.e. that the correct source address is used.
 150         #    These clients also require that the statd notify packet contains
 151         #    the name as the ip address used when the lock was taken out.
 152         #
 153         # Both 2a and 2b are commonly used in lockmanagers since they maximize
 154         # probability that the client will accept the statd notify packet and
 155         # not just ignore it.
 156         # For all IPs we serve, collect info and push to the config database
 157         ctdb_get_pnn
 158
 159         # Construct a sed expression to take catdb output and produce pairs of:
 160         #   server-IP client-IP
 161         # but only for the server-IPs that are hosted on this node.
 162         ctdb_all_ips=$(ctdb ip all | tail -n +2)
 163         sed_expr=$(echo "$ctdb_all_ips" |
 164             awk -v pnn=$pnn 'pnn == $2 { \
 165                 ip = $1; gsub(/\./, "\\.", ip); \
 166                 printf "s/^key.*=.*statd-state@\\(%s\\)@\\([^\"]*\\).*/\\1 \\2/p\n", ip }')
 167
 168         statd_state=$(ctdb catdb ctdb.tdb | sed -n "$sed_expr" | sort)
 169         [ -n "$statd_state" ] || exit 0
 170
 171         smnotify="${CTDB_HELPER_BINDIR}/smnotify"
 172         prev=""
 173         echo "$statd_state" | {
 174             # This all needs to be in the same command group at the
 175             # end of the pipe so it doesn't get lost when the loop
 176             # completes.
 177             items=""
 178             while read sip cip ; do
 179                 # Collect item to delete from the DB
 180                 key="statd-state@${sip}@${cip}"
 181                 item="\"${key}\" \"\""
 182                 items="${items}${items:+${nl}}${item}"
 183
 184                 # NOTE: Consider optimising smnotify to read all the
 185                 # data from stdin and then run it in the background.
 186
 187                 # Reset stateval for each serverip
 188                 [ "$sip" = "$prev" ] || stateval="$state_even"
 189                 # Send notifies for server shutdown
 190                 "$smnotify" --client=$cip --ip=$sip --server=$sip --stateval=$stateval
 191                 "$smnotify" --client=$cip --ip=$sip --server=$NFS_HOSTNAME --stateval=$stateval
 192                 # Send notifies for server startup
 193                 stateval=$(($stateval + 1))
 194                 "$smnotify" --client=$cip --ip=$sip --server=$sip --stateval=$stateval
 195                 "$smnotify" --client=$cip --ip=$sip --server=$NFS_HOSTNAME --stateval=$stateval
 196             done
 197
 198             echo "$items" | ctdb ptrans "ctdb.tdb"
 199         }
 200
 201         # Remove any stale touch files (i.e. for IPs not currently
 202         # hosted on this node and created since the last "update").
 203         # There's nothing else we can do with them at this stage.
 204         echo "$ctdb_all_ips" |
 205             awk -v pnn=$pnn 'pnn != $2 { print $1 }' |
 206             while read sip ; do
 207                 rm -f "statd-state@${sip}@"*
 208             done
 209         ;;
 210 esac