Skip to main content

EBS loss by tag

EBS loss by tag disrupts the state of EBS volume by detaching it from the node (or EC2) instance using volume ID for a certain duration.

  • In case of EBS persistent volumes, the volumes can self-attach and the re-attachment step can be skipped.
  • It tests the deployment sanity (replica availability and uninterrupted service) and recovery workflows of the application pod.

EBS Loss By Tag

Usage

View fault usage
It tests the deployment sanity (replica availability and uninterrupted service) and recovery workflows of the application pod.

Prerequisites

  • Kubernetes > 1.16.
  • Adequate AWS access to attach or detach an EBS volume for the instance.
  • Create a Kubernetes secret that has the AWS access configuration(key) in the CHAOS_NAMESPACE. A sample secret file looks like:
apiVersion: v1
kind: Secret
metadata:
name: cloud-secret
type: Opaque
stringData:
cloud_config.yml: |-
# Add the cloud AWS credentials respectively
[default]
aws_access_key_id = XXXXXXXXXXXXXXXXXXX
aws_secret_access_key = XXXXXXXXXXXXXXX
  • If you change the secret key name (from cloud_config.yml), ensure that you update the AWS_SHARED_CREDENTIALS_FILE environment variable in the chaos experiment with the new name.

Permissions required

Here is an example AWS policy to execute the fault.

View policy for the fault
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": [
"ec2:AttachVolume",
"ec2:DetachVolume"
],
"Resource": "*"
},
{
"Effect": "Allow",
"Action": "ec2:DescribeVolumes",
"Resource": "*"
},
{
"Effect": "Allow",
"Action": [
"ec2:DescribeInstanceStatus",
"ec2:DescribeInstances"
],
"Resource": "*"
}
]
}

Refer to the superset permission/policy to execute all AWS faults.

Default validations

EBS volume is attached to the instance.

Fault tunables

Fault tunables

Mandatory fields

Variables Description Notes
EBS_VOLUME_TAG Provide the common tag for target volumes. It'll be in form of key:value (Ex: 'team:devops')
REGION The region name for the target volumes For example, us-east-1.

Optional fields

Variables Description Notes
VOLUME_AFFECTED_PERC The Percentage of total EBS volumes to target Defaults to 0 (corresponds to 1 volume), provide numeric value only
TOTAL_CHAOS_DURATION The time duration for chaos insertion (sec) Defaults to 30s
CHAOS_INTERVAL The time duration between the attachment and detachment of the volumes (sec) Defaults to 30s
SEQUENCE It defines sequence of chaos execution for multiple volumes Default value: parallel. Supported: serial, parallel
RAMP_TIME Period to wait before and after injection of chaos in sec For example, 30

Fault examples

Common and AWS-specific tunables

Refer to the common attributes and AWS-specific tunables to tune the common tunables for all faults and aws specific tunables.

Target single volume

It will detach a random single EBS volume with the given EBS_VOLUME_TAG tag and REGION region.

Use the following example to tune this:

# contains the tags for the EBS volumes 
apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
name: engine-nginx
spec:
engineState: "active"
chaosServiceAccount: litmus-admin
experiments:
- name: ebs-loss-by-tag
spec:
components:
env:
# tag of the EBS volume
- name: EBS_VOLUME_TAG
value: 'key:value'
# region for the EBS volume
- name: REGION
value: 'us-east-1'
- name: TOTAL_CHAOS_DURATION
VALUE: '60'

Target percent of volumes

It will detach the VOLUME_AFFECTED_PERC percentage of EBS volumes with the given EBS_VOLUME_TAG tag and REGION region.

Use the following example to tune it:

# target percentage of the EBS volumes with the provided tag
apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
name: engine-nginx
spec:
engineState: "active"
chaosServiceAccount: litmus-admin
experiments:
- name: ebs-loss-by-tag
spec:
components:
env:
# percentage of EBS volumes filter by tag
- name: VOLUME_AFFECTED_PERC
value: '100'
# tag of the EBS volume
- name: EBS_VOLUME_TAG
value: 'key:value'
# region for the EBS volume
- name: REGION
value: 'us-east-1'
- name: TOTAL_CHAOS_DURATION
VALUE: '60'