jepsen: add cluster reconfiguration nemesis

script/jepsen.garage/Vagrantfile

@@ -27,4 +27,5 @@ Vagrant.configure("2") do |config|
   config.vm.define "n3" do |config| vm(config, "n3", "192.168.56.23") end
   config.vm.define "n4" do |config| vm(config, "n4", "192.168.56.24") end
   config.vm.define "n5" do |config| vm(config, "n5", "192.168.56.25") end
+  config.vm.define "n6" do |config| vm(config, "n6", "192.168.56.26") end
 end

script/jepsen.garage/nodes.vagrant

@@ -3,3 +3,4 @@
 192.168.56.23
 192.168.56.24
 192.168.56.25
+192.168.56.26

script/jepsen.garage/src/jepsen/garage.clj

@@ -10,6 +10,7 @@
     [jepsen.os.debian :as debian]
     [jepsen.garage
      [daemon :as grg]
+     [nemesis :as grgNemesis]
      [reg :as reg]
      [set :as set]]))
 
@@ -20,6 +21,11 @@
    "set1" set/workload1
    "set2" set/workload2})
 
+(def scenari
+  "A map of scenari to the associated nemesis"
+  {"cp" grgNemesis/scenario-cp
+   "r"  grgNemesis/scenario-r})
+
 (def patches
   "A map of patch names to Garage builds"
   {"default" "v0.9.0"
@@ -31,6 +37,9 @@
   [["-p" "--patch NAME" "Garage patch to use"
     :default "default"
     :validate [patches (cli/one-of patches)]]
+   ["-s" "--scenario NAME" "Nemesis scenario to run"
+    :default "cp"
+    :validate [scenari (cli/one-of scenari)]]
    ["-r" "--rate HZ" "Approximate number of requests per second, per thread."
     :default  10
     :parse-fn read-string
@@ -40,7 +49,7 @@
     :parse-fn parse-long
     :validate [pos? "Must be a positive integer."]]
    ["-w" "--workload NAME" "Workload of test to run"
-    :default "reg"
+    :default "reg1"
     :validate [workloads (cli/one-of workloads)]]])
 
 (defn garage-test
@@ -48,6 +57,7 @@
   :concurrency, ...), constructs a test map."
   [opts]
   (let [workload ((get workloads (:workload opts)) opts)
+        scenario ((get scenari (:scenario opts)) opts)
         garage-version (get patches (:patch opts))]
     (merge tests/noop-test
            opts
@@ -60,25 +70,14 @@
                                 (->>
                                   (:generator workload)
                                   (gen/stagger (/ (:rate opts)))
-                                  (gen/nemesis
+                                  (gen/nemesis (:generator scenario))
-                                    (cycle [(gen/sleep 5)
-                                            {:type :info, :f :partition-start}
-                                            (gen/sleep 5)
-                                            {:type :info, :f :clock-scramble}
-                                            (gen/sleep 5)
-                                            {:type :info, :f :partition-stop}
-                                            (gen/sleep 5)
-                                            {:type :info, :f :clock-scramble}]))
                                   (gen/time-limit (:time-limit opts)))
                                 (gen/log "Healing cluster")
                                 (gen/nemesis (gen/once {:type :info, :f :partition-stop}))
                                 (gen/log "Waiting for recovery")
                                 (gen/sleep 10)
                                 (gen/clients (:final-generator workload)))
-            :nemesis          (nemesis/compose
+            :nemesis          (:nemesis scenario)
-                                {{:partition-start :start
-                                  :partition-stop :stop} (nemesis/partition-random-halves)
-                                 {:clock-scramble :scramble} (nemesis/clock-scrambler 20.0)})
             :checker          (checker/compose
                                 {:perf (checker/perf)
                                  :workload (:checker workload)})

script/jepsen.garage/src/jepsen/garage/nemesis.clj

@@ -0,0 +1,91 @@
+(ns jepsen.garage.nemesis
+  (:require [clojure.tools.logging :refer :all]
+            [jepsen [control :as c]
+             [core :as jepsen]
+             [generator :as gen]
+             [nemesis :as nemesis]]
+            [jepsen.garage.daemon :as grg]
+            [jepsen.control.util :as cu]))
+
+(defn configure-present!
+  "Configure node to be active in new cluster layout"
+  [test node]
+  (info "configure-present!" node)
+  (let [node-id (c/on node (c/exec grg/binary :node :id :-q))]
+   (c/on
+     (jepsen/primary test)
+     (c/exec grg/binary :layout :assign (subs node-id 0 16) :-c :1G))))
+
+(defn configure-absent!
+  "Configure node to be active in new cluster layout"
+  [test node]
+  (info "configure-absent!" node)
+  (let [node-id (c/on node (c/exec grg/binary :node :id :-q))]
+   (c/on
+     (jepsen/primary test)
+     (c/exec grg/binary :layout :assign (subs node-id 0 16) :-g))))
+
+(defn finalize-config!
+  "Apply the proposed cluster layout"
+  [test]
+  (let [layout-show (c/on (jepsen/primary test) (c/exec grg/binary :layout :show))
+        [_ layout-next-version] (re-find #"apply --version (\d+)\n" layout-show)]
+    (info "layout show: " layout-show "; next-version: " layout-next-version)
+    (c/on (jepsen/primary test)
+          (c/exec grg/binary :layout :apply :--version layout-next-version))))
+
+(defn reconfigure-subset
+  "Reconfigure cluster with only a subset of nodes"
+  [cnt]
+  (reify nemesis/Nemesis
+    (setup! [this test] this)
+
+    (invoke! [this test op] op
+      (case (:f op)
+        :start
+          (let [[keep-nodes remove-nodes]
+                (->> (:nodes test)
+                     shuffle
+                     (split-at cnt))]
+            (info "layout split: keep " keep-nodes ", remove " remove-nodes)
+            (run! #(configure-present! test %) keep-nodes)
+            (run! #(configure-absent! test %) remove-nodes)
+            (finalize-config! test)
+            (assoc op :value keep-nodes))
+        :stop
+          (do
+            (info "layout un-split: all nodes=" (:nodes test))
+            (run! #(configure-present! test %) (:nodes test))
+            (finalize-config! test)
+            (assoc op :value (:nodes test)))))
+
+    (teardown! [this test] this)))
+
+(defn scenario-cp
+  "Clock scramble + parittion scenario"
+  [opts]
+  {:generator      (cycle [(gen/sleep 5)
+                           {:type :info, :f :partition-start}
+                           (gen/sleep 5)
+                           {:type :info, :f :clock-scramble}
+                           (gen/sleep 5)
+                           {:type :info, :f :partition-stop}
+                           (gen/sleep 5)
+                           {:type :info, :f :clock-scramble}])
+   :nemesis        (nemesis/compose
+                     {{:partition-start :start
+                       :partition-stop :stop} (nemesis/partition-random-halves)
+                      {:clock-scramble :scramble} (nemesis/clock-scrambler 20.0)})})
+
+(defn scenario-r
+  "Cluster reconfiguration scenario"
+  [opts]
+  {:generator      (cycle [(gen/sleep 5)
+                           {:type :info, :f :reconfigure-start}
+                           (gen/sleep 5)
+                           {:type :info, :f :reconfigure-start}
+                           (gen/sleep 5)
+                           {:type :info, :f :reconfigure-stop}])
+   :nemesis        (nemesis/compose
+                     {{:reconfigure-start :start
+                       :reconfigure-stop :stop} (reconfigure-subset 3)})})