Example 3: 2 node cluster, 1 peer successfully joins, 1 aborts

• Nodes A and B fully in the cluster

• Local state before (1): {:pairs {:a :b, :b :a}}

• C and D want to join

• C sends prepare-join-cluster (1)

• D sends prepare-join-cluster (2)

• A, B, C, and D play the log

• B encounters (1)

  • Pre: {:pairs {:a :b, :b :a}}
  • Post: {:pairs {:a :b, :b :a} :prepared {:b :c}}
  • determines B will attach to C. Records this in the local state.
  • adds watch to C
  • sends notify-join-cluster (3)

• A, C, and D encounter (1)

  • Pre: {:pairs {:a :b, :b :a}}
  • Post: {:pairs {:a :b, :b :a} :prepared {:b :c}}
  • determines B will attach to C. Records this in the local state.
  • no reactions

• A, B, C, D encounter (2)

  • Pre: {:pairs {:a :b, :b :a} :prepared {:b :c}}
  • Post: {:pairs {:a :b, :b :a} :prepared {:b :c}}
  • determines D cannot attach to any nodes. Aborts.
  • D sends abort-join-cluster to the log, optionally tries to join again later
  • no reactions

• C encounters (3)

  • Pre: {:pairs {:a :b, :b :a} :prepared {:b :c}}
  • Post: {:pairs {:a :b, :b :a} :accepted {:b :c}}
  • adds a watch to A
  • sends accept-join-cluster (4)

• A and B encounter (3)

  • Pre: {:pairs {:a :b, :b :a} :prepared {:b :c}}
  • Post: {:pairs {:a :b, :b :a} :accepted {:b :c}}
  • ignore

• B encounters (4)

  • Pre: {:pairs {:a :b, :b :a} :prepared {:b :c}}
  • Post: {:pairs {:a :c, :b :c, :c :a}}
  • B drops its watch form A

• A and C encounter (4)

  • Pre: {:pairs {:a :b, :b :a} :prepared {:b :c}}
  • Post: {:pairs {:a :c, :b :c, :c :a}}
  • C flushes its outbox
  • ignore