Use eksctl when creating the IAM role and trust relationship

[ruzickap]

Description of your changes

Simplify using IRSA by using eksctl for creating IAM role and IAM role trust relationship.

[chlunde]

I'm not sure if we should remove the current documentation, because not everyone uses eksctl and it is nice to show the low level AWS pieces required for IRSA, if someone wants to reproduce it using crossplane, terraform or another tool.

Maybe you can add it using <details> and <summary>?

<details>
<summary>Create IAM role with trust relationship using `eksctl`...</summary>
<p>
method one desc..
</p>

<details>
<summary>Create IAM role with trust relationship using `aws` cli...</summary>
<p>
method two desc..
</p>
</details>  

Create IAM role with trust relationship using `eksctl`...

eksctl create iamserviceaccount --cluster <cluster-name> --region <region> --name="$SERVICE_ACCOUNT_NAME" --namespace="$SERVICE_ACCOUNT_NAMESPACE" --role-name="$IAM_ROLE_NAME" --role-only --attach-policy-arn="arn:aws:iam::aws:policy/AdministratorAccess" --approve

[dfallert-rcd]

some of the variables use the <variable-name> syntax, and others use $VARIABLE_NAME. For consistency, I recommend choosing one or the other.

[ruzickap]

Yeah... In some parts of the documentation it is being used <cluster-name> or <region> and somewhere else ${SERVICE_ACCOUNT_NAMESPACE}.

I would prefer to use bash variable like ${CLUSTER_NAME} everywhere if you agree...?

[ruzickap]

Fixed...

[chlunde]

@ruzickap looks good, I see you did some final touches, now even shellcheck would approve 😄 If you're done I think we can merge. OK?

[ruzickap]

Sure... Go ahead...