# Adding and ordering steps
<a name="recovery-plans-steps"></a>

Steps are numbered from 1 and run in ascending order. A plan can contain up to 20 steps and up to 100 source servers in total across all of its steps.

The following rules apply to steps:
+ A source server can appear in only one step within a single plan. The same source server can appear in more than one plan.
+ A wait step cannot be the first step in a plan, because there is nothing to wait for.
+ A wait step must be between 1 and 120 minutes.
+ You cannot change a step's type after you create it. To change a server step into a wait step, delete it and create a new one.

To add a server step with the AWS CLI, use the `create-recovery-plan-step` command with a `serverStepConfiguration`. Servers that you do not give an `impactLevel` default to `CRITICAL`.

```
aws drs create-recovery-plan-step \
    --recovery-plan-arn {{PLAN_ARN}} \
    --step-name "Database tier" \
    --configuration '{
        "serverStepConfiguration": {
            "servers": [
                {"serverArn": "{{SERVER_ARN_1}}", "impactLevel": "CRITICAL"},
                {"serverArn": "{{SERVER_ARN_2}}", "impactLevel": "OPTIONAL"}
            ]
        }
    }'
```

To add a wait step, use a `waitStepConfiguration` instead.

```
aws drs create-recovery-plan-step \
    --recovery-plan-arn {{PLAN_ARN}} \
    --step-name "Wait for database startup" \
    --configuration '{"waitStepConfiguration": {"waitDurationMinutes": 10}}'
```

By default, a new step is added to the end of the plan. To insert a step at a specific position, include `--step-order`; the steps at and after that position move down by one. To reorder the steps that a plan already has, use `reorder-recovery-plan-steps` and pass the complete list of step ARNs in the order that you want.

```
aws drs reorder-recovery-plan-steps \
    --recovery-plan-arn {{PLAN_ARN}} \
    --ordered-step-arns {{STEP_ARN_2}} {{STEP_ARN_1}} {{STEP_ARN_3}}
```

To change the servers in a server step, use `update-recovery-plan-step`. The server list is replaced in full, so include every server that you want the step to keep.

## Finding a source server ARN
<a name="recovery-plans-server-identifiers"></a>

The step APIs identify a source server by its ARN, in the `serverArn` field. A source server ARN has the following format.

```
arn:{{partition}}:drs:{{region}}:{{account-id}}:source-server/s-{{EXAMPLE1}}
```

To find the ARNs of your source servers, use `describe-source-servers` and read the `arn` field of each entry in the response.

```
aws drs describe-source-servers \
    --query 'items[].{arn:arn,hostname:sourceProperties.identificationHints.hostname}'
```

**Note**  
The step APIs take a full ARN in `serverArn`, but `start-recovery-plan-execution` takes the short source server ID in `sourceServerID` instead, for example `s-{{EXAMPLE1}}`. The short ID is the last part of the ARN, after `source-server/`.