Remove --single-mode option

Replaced manually specified option by a function that can detect mode
automatically.

Closes #36

Author: ligurio

src/tarantool/db.clj

@@ -196,6 +196,13 @@
   (let [p (jepsen/primary test)]
     (if (= node p) true false)))
 
+(defn is-single-mode?
+  [test]
+  (let [n (count (:nodes test))]
+    (cond
+      (= n 1) true
+      :else false)))
+
 (defn configure!
   "Configure instance"
   [test node]
@@ -207,7 +214,7 @@
     (c/exec :echo (-> "tarantool/jepsen.lua" io/resource slurp
                       (str/replace #"%TARANTOOL_REPLICATION%" (replica-set test))
                       (str/replace #"%TARANTOOL_IS_READ_ONLY%" (boolean-to-str read-only))
-                      (str/replace #"%TARANTOOL_SINGLE_MODE%" (boolean-to-str (:single-mode test)))
+                      (str/replace #"%TARANTOOL_SINGLE_MODE%" (boolean-to-str (is-single-mode? test)))
                       (str/replace #"%TARANTOOL_DATA_ENGINE%" (:engine test)))
             :> "/etc/tarantool/instances.enabled/jepsen.lua")
     (c/exec :cp "/etc/tarantool/instances.enabled/jepsen.lua" "/etc/tarantool/instances.available")))

src/tarantool/runner.clj

@@ -73,9 +73,6 @@
      :parse-fn keyword
      :missing (str "--workload " (cli/one-of workloads))
      :validate [workloads (cli/one-of workloads)]]
-    [nil "--single-mode"
-     "Use a single Tarantool instance"
-     :default false]
     ["-e" "--engine NAME"
      "What Tarantool data engine should we use?"
      :default "memtx"]])
@@ -134,7 +131,6 @@
             :os        ubuntu/os
             :db        (db/db (:version opts))
             :engine    (:engine opts)
-            :single-mode (:single-mode opts)
             :pure-generators true
             :generator gen
             :checker   (checker/compose {:perf        (checker/perf)