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OpenStack Cloud deployment with Terraform and Salt

This sub directory contains the cloud specific part for usage of this repository with Openstack. Looking for another provider? See Getting started

Quickstart

This is a very short quickstart guide.

For detailed information and deployment options have a look at terraform.tfvars.example.

  1. Rename terraform.tfvars:

    mv terraform.tfvars.example terraform.tfvars

    Now, the created file must be configured to define the deployment.

    Note: Find some help in for IP addresses configuration below in Customization.

  2. Generate private and public keys for the cluster nodes without specifying the passphrase:

    Alternatively, you can set the pre_deployment variable to automatically create the cluster ssh keys.

    mkdir -p ../salt/sshkeys
ssh-keygen -f ../salt/sshkeys/cluster.id_rsa -q -P ""

    The key files need to have same name as defined in terraform.tfvars.

  3. Adapt saltstack pillars manually or set the pre_deployment variable to automatically copy the example pillar files.

  4. Configure Terraform Access to OpenStack

    pip install python-openstackclient

    export OS_CLOUD=my-lab
export TF_VAR_openstack_auth_url=$(openstack configuration show -c auth.auth_url -f value)
export TF_VAR_openstack_password=$(openstack configuration show -c auth.password -f value --unmask)

    You should be able to deploy now.

    To verify if you can access your OpenStack cloud, try a openstack image list.

  5. Prepare a NFS share with the installation sources

    Add the NFS paths to terraform.tfvars.

    • Note: Find some help in SAP software documentation

    • Optional: enable NFS server deployment (see terraform.tfvars) and provision it before everything else. After that, copy files and proceed as usual.

    terraform apply -target="module.nfs_server"
rsync -avPc --delete -e "ssh -l sles -i id_rsa -J sles@$(terraform output -raw bastion_public_ip)" --rsync-path="sudo rsync" ~/Downloads/SAP/sapinst/ $(terraform output -raw nfssrv_ip):/mnt_permanent/sapdata/sapinst/

  6. Deploy

    The deployment can now be started with:

    terraform init
terraform workspace new myexecution # optional
terraform workspace select myexecution # optional
terraform plan
terraform apply

    To get rid of the deployment, destroy the created infrastructure with:

    terraform destroy

Bastion

By default, the bastion machine is enabled in OpenStack (it can be disabled for private deployments), which will have the unique public IP address of the deployed resource group. Connect using ssh and the selected admin user with: ssh {admin_user}@{bastion_ip} -i {private_key_location}

To log to hana and others instances, use:

ssh -o ProxyCommand="ssh -W %h:%p {admin_user}@{bastion_ip} -i {private_key_location} -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no" {admin_user}@{private_hana_instance_ip} -i {private_key_location} -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no

To disable the bastion use:

bastion_enabled = false

Destroy the created infrastructure with:

terraform destroy

Highlevel description

This Terraform configuration deploys SAP HANA in a High-Availability Cluster on SUSE Linux Enterprise Server for SAP Applications in OpenStack.

Highlevel description

The infrastructure deployed includes:

  • virtual network
  • subnets within the virtual network
  • Network Security Groups for access to the instances created. The Bastion host will only be reachable via SSH. In the subnetwork any traffic is allowed.
  • cinder volumes or ephemeral volumes
  • virtual machines
  • shared NFS filesystems (if enabled)

By default, this configuration will create 3 instances in OpenStack: one for support services (mainly iSCSI) and 2 cluster nodes, but this can be changed to deploy more cluster nodes as needed.

Once the infrastructure is created by Terraform, the servers are provisioned with Salt.

Customization

In order to deploy the environment, different configurations are available through the terraform variables. These variables can be configured using a terraform.tfvars file. An example is available in terraform.tfvars.example. To find all the available variables check the variables.tf file.

QA deployment

The project has been created in order to provide the option to run the deployment in a Test or QA mode. This mode only enables the packages coming properly from SLE channels, so no other packages will be used. Set offline_mode = true in terraform.tfvars to enable it.

Pillar files configuration

Besides the terraform.tfvars file usage to configure the deployment, a more advanced configuration is available through pillar files customization. Find more information here.

Use already existing network resources

The usage of already existing network resources (subnet, firewall rules, etc) can be done configuring the terraform.tfvars file and adjusting some variables. The example of how to use them is available at terraform.tfvars.example.

Autogenerated network addresses

The assignment of the addresses of the nodes in the network can be automatically done in order to avoid this configuration. For that, basically, remove or comment all the variables related to the ip addresses (more information in variables.tf). With this approach all the addresses are retrieved based in the provided virtual network addresses range (vnet_address_range).

Note: If you are specifying the IP addresses manually, make sure these are valid IP addresses. They should not be currently in use by existing instances. In case of shared account usage, it is recommended to set unique addresses with each deployment to avoid using same addresses.

Example based on 10.0.0.0/24 address range.

Service Variable Addresses Comments
iSCSI server iscsi_srv_ip 10.0.0.4
Monitoring monitoring_srv_ip 10.0.0.5
HANA IPs hana_ips 10.0.0.10, 10.0.0.11
HANA cluster vIP hana_cluster_vip 10.0.2.12 Only used if HA is enabled in HANA
HANA cluster vIP secondary hana_cluster_vip_secondary 10.0.0.13 Only used if the Active/Active setup is used
DRBD IPs drbd_ips 10.0.0.20, 10.0.0.21
DRBD cluster vIP drbd_cluster_vip 10.0.0.22
S/4HANA or NetWeaver IPs netweaver_ips 10.0.0.30, 10.0.0.31, 10.0.0.32, 10.0.0.33 Addresses for the ASCS, ERS, PAS and AAS. The sequence will continue if there are more AAS machines
S/4HANA or NetWeaver virtual IPs netweaver_virtual_ips 10.0.0.34, 10.0.0.35, 10.0.0.36, 10.0.0.37 The first virtual address will be the next in the sequence of the regular S/4HANA or NetWeaver addresses

Advanced Customization

Terraform Parallelism

When deploying many scale-out nodes, e.g. 8 or 10, you should must pass the -nparallelism=n🔗 parameter to terraform apply operations.

It "limit[s] the number of concurrent operation as Terraform walks the graph."

The default value of 10 is not sufficient because not all HANA cluster nodes will get provisioned at the same. A value of e.g. 30 should not hurt for most use-cases.

Troubleshooting

In case you have some issue, take a look at this troubleshooting guide.