SSH or gain command line access to XenServer

First we need to enable the Pool to allow auto starting
Second we will need to turn on the auto_poweron to true

In the following examples replace the UUIDs with your UUIDs

Find Pool UUID

You can find the pool UUID by running the “xe pool-list” Command. Note: you’ll still have a pool even if there is only a single server.

# xe pool-list
uuid ( RO) : 2e587aeb-de94-hf29-3eda-923d8he634fe

Enable auto_poweron for the pool

xe pool-param-set uuid=2e587aeb-de94-hf29-3eda-923d8he634fe other-config:auto_poweron=true

Verify that it is enabled

xe pool-param-list uuid=2e587aeb-de94-hf29-3eda-923d8he634fe  | grep auto_poweron

List VM UUID’s

Locate the UUID’s of the VM’s you want to start

# xe vm-list
uuid ( RO)           : 521be58a-3495-ea29-02a0-85ffcda06583
     name-label ( RW): CentOS 7
    power-state ( RO): running

Enable auto start

Run the following command for each VM you want to auto start. Change the UUID to the UUID of the vm you want to start.

xe pool-param-set uuid=521be58a-3495-ea29-02a0-85ffcda06583  other-config:auto_poweron=true

Print parameter settings

Use the following command to verify that the auto_poweron option is enabled.

xe vm-param-list uuid=521be58a-3495-ea29-02a0-85ffcda06583 | grep -i poweron | cut -d";" -f1

Example output

                      other-config (MRW): auto_poweron: true

https://support.citrix.com/article/CTX133910