SYN flood scenario (#668)

* scenario config file

Signed-off-by: Tullio Sebastiani <tsebasti@redhat.com>

* syn flood plugin

Signed-off-by: Tullio Sebastiani <tsebasti@redhat.com>

* run_krkn.py updaated

Signed-off-by: Tullio Sebastiani <tsebasti@redhat.com>

* requirements.txt + documentation + config.yaml

* set node selector defaults to worker

Signed-off-by: Tullio Sebastiani <tsebasti@redhat.com>

---------

Signed-off-by: Tullio Sebastiani <tsebasti@redhat.com>

scenarios/kube/syn_flood.yaml

@@ -0,0 +1,16 @@
+packet-size: 120 # hping3 packet size
+window-size: 64 # hping 3 TCP window size
+duration: 10 # chaos scenario duration
+namespace: default # namespace where the target service(s) are deployed
+target-service: elasticsearch # target service name (if set target-service-label must be empty)
+target-port: 9200 # target service TCP port
+target-service-label : "" # target service label, can be used to target multiple target at the same time
+                          # if they have the same label set (if set target-service must be empty)
+number-of-pods: 2 # number of attacker pod instantiated per each target
+image: quay.io/krkn-chaos/krkn-syn-flood:v1.0.0 # syn flood attacker container image
+attacker-nodes:                       # this will set the node affinity to schedule the attacker node. Per each node label selector
+    node-role.kubernetes.io/worker:   # can be specified multiple values in this way the kube scheduler will schedule the attacker pods
+      - ""                            # in the best way possible based on the provided labels. Multiple labels can be specified
+                                      # set empty value  `attacker-nodes: {}`  to let kubernetes schedule the pods
+
+