Netflix · justinsb · Sep 13, 2013 · Sep 13, 2013 · Sep 13, 2013 · Sep 13, 2013
diff --git a/src/main/java/com/netflix/simianarmy/CloudClient.java b/src/main/java/com/netflix/simianarmy/CloudClient.java
@@ -17,6 +17,7 @@
  */
 package com.netflix.simianarmy;
 
+import java.util.List;
 import java.util.Map;
 
 
@@ -88,4 +89,33 @@ public interface CloudClient {
      */
     void createTagsForResources(Map<String, String> keyValueMap, String... resourceIds);
 
+    /**
+     * Lists all EBS volumes attached to the specified instance.
+     *
+     * @param instanceId
+     *            the instance id
+     * @param includeRoot
+     *            if the root volume is on EBS, should we include it?
+     *
+     * @throws NotFoundException
+     *             if the instance no longer exists or was already terminated after the crawler discovered it then you
+     *             should get a NotFoundException
+     */
+    List<String> listAttachedVolumes(String instanceId, boolean includeRoot);
+
+    /**
+     * Detaches an EBS volumes from the specified instance.
+     *
+     * @param instanceId
+     *            the instance id
+     * @param volumeId
+     *            the volume id
+     * @param force
+     *            if we should force-detach the volume.  Probably best not to use on high-value volumes.
+     *
+     * @throws NotFoundException
+     *             if the instance no longer exists or was already terminated after the crawler discovered it then you
+     *             should get a NotFoundException
+     */
+    void detachVolume(String instanceId, String volumeId, boolean force);
 }
diff --git a/src/main/java/com/netflix/simianarmy/basic/chaos/BasicChaosMonkey.java b/src/main/java/com/netflix/simianarmy/basic/chaos/BasicChaosMonkey.java
@@ -42,6 +42,7 @@
 import com.netflix.simianarmy.chaos.ChaosEmailNotifier;
 import com.netflix.simianarmy.chaos.ChaosMonkey;
 import com.netflix.simianarmy.chaos.ChaosType;
+import com.netflix.simianarmy.chaos.DetachVolumesChaosType;
 import com.netflix.simianarmy.chaos.ShutdownInstanceChaosType;
 
 /**
@@ -90,6 +91,7 @@ public BasicChaosMonkey(ChaosMonkey.Context ctx) {
 
         allChaosTypes = Lists.newArrayList();
         allChaosTypes.add(new ShutdownInstanceChaosType(cfg));
+        allChaosTypes.add(new DetachVolumesChaosType(cfg));
 
         TimeUnit freqUnit = ctx.scheduler().frequencyUnit();
         long units = freqUnit.convert(close.getTimeInMillis() - open.getTimeInMillis(), TimeUnit.MILLISECONDS);

diff --git a/src/main/java/com/netflix/simianarmy/chaos/ChaosType.java b/src/main/java/com/netflix/simianarmy/chaos/ChaosType.java
@@ -16,7 +16,7 @@ public abstract class ChaosType {
     private static final Logger LOGGER = LoggerFactory.getLogger(ChaosType.class);
 
     /**
-     * Configuration for this chaos type
+     * Configuration for this chaos type.
      */
     private final MonkeyConfiguration config;
 
@@ -77,6 +77,13 @@ public String getKey() {
      * detach.
      */
     public boolean canApply(CloudClient cloudClient, String instanceId) {
+        return isEnabled();
+    }
+
+    /**
+     * Returns whether we are enabled.
+     */
+    public boolean isEnabled() {
         return enabled;
     }
 
@@ -94,6 +101,7 @@ public static ChaosType parse(List<ChaosType> all, String chaosTypeName) {
                 return chaosType;
             }
         }
-        throw new IllegalArgumentException("Unknown chaos type: " + chaosTypeName);
+        throw new IllegalArgumentException("Unknown chaos type value: "
+                + chaosTypeName);
     }
 }
diff --git a/src/main/java/com/netflix/simianarmy/chaos/DetachVolumesChaosType.java b/src/main/java/com/netflix/simianarmy/chaos/DetachVolumesChaosType.java
@@ -0,0 +1,64 @@
+package com.netflix.simianarmy.chaos;
+
+import java.util.List;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.netflix.simianarmy.CloudClient;
+import com.netflix.simianarmy.MonkeyConfiguration;
+import com.netflix.simianarmy.basic.chaos.BasicChaosMonkey;
+
+/**
+ * We force-detach all the EBS volumes.
+ *
+ * This is supposed to simulate a catastrophic failure of EBS, however the instance will (possibly) still keep running;
+ * e.g. it should continue to respond to pings.
+ */
+public class DetachVolumesChaosType extends ChaosType {
+    /** The Constant LOGGER. */
+    private static final Logger LOGGER = LoggerFactory.getLogger(BasicChaosMonkey.class);
+
+    /**
+     * Constructor.
+     *
+     * @param config
+     *            Configuration to use
+     */
+    public DetachVolumesChaosType(MonkeyConfiguration config) {
+        super(config, "DetachVolumes");
+    }
+
+    /**
+     * Strategy can be applied iff there are any EBS volumes attached.
+     */
+    @Override
+    public boolean canApply(CloudClient cloudClient, String instanceId) {
+        // The test mocks don't implement listAttachedVolumes
+        // so check for enabled first
+        if (!isEnabled()) {
+            return false;
+        }
+
+        List<String> volumes = cloudClient.listAttachedVolumes(instanceId, false);
+        if (volumes.isEmpty()) {
+            LOGGER.debug("Can't apply strategy: no non-root EBS volumes");
+            return false;
+        }
+
+        return super.canApply(cloudClient, instanceId);
+    }
+
+    /**
+     * Force-detaches all attached EBS volumes from the instance.
+     */
+    @Override
+    public void apply(CloudClient cloudClient, String instanceId) {
+        // IDEA: We could have a strategy where we detach some of the volumes...
+        boolean force = true;
+        for (String volumeId : cloudClient.listAttachedVolumes(instanceId, false)) {
+            cloudClient.detachVolume(instanceId, volumeId, force);
+        }
+    }
+
+}
diff --git a/src/main/java/com/netflix/simianarmy/client/aws/AWSClient.java b/src/main/java/com/netflix/simianarmy/client/aws/AWSClient.java
@@ -45,8 +45,11 @@
 import com.amazonaws.services.ec2.model.DescribeSnapshotsResult;
 import com.amazonaws.services.ec2.model.DescribeVolumesRequest;
 import com.amazonaws.services.ec2.model.DescribeVolumesResult;
+import com.amazonaws.services.ec2.model.DetachVolumeRequest;
+import com.amazonaws.services.ec2.model.EbsInstanceBlockDevice;
 import com.amazonaws.services.ec2.model.Image;
 import com.amazonaws.services.ec2.model.Instance;
+import com.amazonaws.services.ec2.model.InstanceBlockDeviceMapping;
 import com.amazonaws.services.ec2.model.Reservation;
 import com.amazonaws.services.ec2.model.Snapshot;
 import com.amazonaws.services.ec2.model.Tag;
@@ -58,8 +61,10 @@
 import com.amazonaws.services.elasticloadbalancing.model.LoadBalancerDescription;
 import com.amazonaws.services.simpledb.AmazonSimpleDB;
 import com.amazonaws.services.simpledb.AmazonSimpleDBClient;
+import com.google.common.base.Strings;
 import com.netflix.simianarmy.CloudClient;
 import com.netflix.simianarmy.NotFoundException;
+
 import org.apache.commons.lang.Validate;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -531,4 +536,59 @@ public List<Image> describeImages(String... imageIds) {
         LOGGER.info(String.format("Got %d AMIs in region %s.", images.size(), region));
         return images;
     }
+
+
+    @Override
+    public void detachVolume(String instanceId, String volumeId, boolean force) {
+        Validate.notEmpty(instanceId);
+        LOGGER.info(String.format("Detach volumes from instance %s in region %s.", instanceId, region));
+        try {
+            DetachVolumeRequest detachVolumeRequest = new DetachVolumeRequest();
+            detachVolumeRequest.setForce(force);
+            detachVolumeRequest.setInstanceId(instanceId);
+            detachVolumeRequest.setVolumeId(volumeId);
+            ec2Client().detachVolume(detachVolumeRequest);
+        } catch (AmazonServiceException e) {
+            if (e.getErrorCode().equals("InvalidInstanceID.NotFound")) {
+                throw new NotFoundException("AWS instance " + instanceId + " not found", e);
+            }
+            throw e;
+        }
+    }
+
+    @Override
+    public List<String> listAttachedVolumes(String instanceId, boolean includeRoot) {
+        Validate.notEmpty(instanceId);
+        LOGGER.info(String.format("Listing volumes attached to instance %s in region %s.", instanceId, region));
+        try {
+            List<String> volumeIds = new ArrayList<String>();
+            for (Instance instance : describeInstances(instanceId)) {
+                String rootDeviceName = instance.getRootDeviceName();
+
+                for (InstanceBlockDeviceMapping ibdm : instance.getBlockDeviceMappings()) {
+                    EbsInstanceBlockDevice ebs = ibdm.getEbs();
+                    if (ebs == null) {
+                        continue;
+                    }
+
+                    String volumeId = ebs.getVolumeId();
+                    if (Strings.isNullOrEmpty(volumeId)) {
+                        continue;
+                    }
+
+                    if (!includeRoot && rootDeviceName != null && rootDeviceName.equals(ibdm.getDeviceName())) {
+                        continue;
+                    }
+
+                    volumeIds.add(volumeId);
+                }
+            }
+            return volumeIds;
+        } catch (AmazonServiceException e) {
+            if (e.getErrorCode().equals("InvalidInstanceID.NotFound")) {
+                throw new NotFoundException("AWS instance " + instanceId + " not found", e);
+            }
+            throw e;
+        }
+    }
 }
diff --git a/src/main/resources/chaos.properties b/src/main/resources/chaos.properties
@@ -19,6 +19,7 @@ simianarmy.chaos.ASG.maxTerminationsPerDay = 1.0
 
 # Strategies
 simianarmy.chaos.shutdowninstance.enabled = true
+simianarmy.chaos.detachvolumes.enabled = true
 
 # enable a specific ASG
 # simianarmy.chaos.ASG.<asgName>.enabled = true

diff --git a/src/test/java/com/netflix/simianarmy/TestMonkeyContext.java b/src/test/java/com/netflix/simianarmy/TestMonkeyContext.java
@@ -132,6 +132,17 @@ public void deleteImage(String imageId) {
             @Override
             public void deleteLaunchConfiguration(String launchConfigName) {
             }
+
+            @Override
+            public List<String> listAttachedVolumes(String instanceId, boolean includeRoot) {
+                throw new UnsupportedOperationException();
+            }
+
+            @Override
+            public void detachVolume(String instanceId, String volumeId,
+                    boolean force) {
+                throw new UnsupportedOperationException();
+            }
         };
     }
 

diff --git a/src/test/java/com/netflix/simianarmy/chaos/TestChaosMonkeyContext.java b/src/test/java/com/netflix/simianarmy/chaos/TestChaosMonkeyContext.java
@@ -223,6 +223,17 @@ public void deleteImage(String imageId) {
             @Override
             public void deleteLaunchConfiguration(String launchConfigName) {
             }
+
+            @Override
+            public List<String> listAttachedVolumes(String instanceId, boolean includeRoot) {
+                throw new UnsupportedOperationException();
+            }
+
+            @Override
+            public void detachVolume(String instanceId, String volumeId,
+                    boolean force) {
+                throw new UnsupportedOperationException();
+            }
         };
     }