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Rancher Kubernetes Engine 2, VMWare vSAN, VMWare vSphere, SLES for SAP 15 SP4, SAP Data Intelligence 3

SAP Data Intelligence 3 on Rancher Kubernetes Engine 2 using VMware vSAN and vSphere

SUSE Best Practices
Containerization SAP
Authors
Dr. Ulrich Schairer, SAP Solutions Architect (SUSE)
Kevin Klinger, SAP Solutions Architect (SUSE)
Image
SUSE Linux Enterprise Server for SAP Applications15 SP4
Rancher Kubernetes Engine 2
SAP Data Intelligence 3
Date: 2023-07-24

SAP Data Intelligence 3 is the tool set to govern big amounts of data, and it runs fully containerized. This document describes the installation and configuration of SAP Data Intelligence 3 deployed on SUSE's RKE2 and VMWare vsphere and vsan.

Disclaimer: Documents published as part of the SUSE Best Practices series have been contributed voluntarily by SUSE employees and third parties. They are meant to serve as examples of how particular actions can be performed. They have been compiled with utmost attention to detail. However, this does not guarantee complete accuracy. SUSE cannot verify that actions described in these documents do what is claimed or whether actions described have unintended consequences. SUSE LLC, its affiliates, the authors, and the translators may not be held liable for possible errors or the consequences thereof.

1 Introduction

This guide describes the on-premises installation of SAP Data Intelligence 3.3 on top of VMware vSphere/vSAN cluster and Rancher Kubernetes Engine (RKE) 2. This guide does not provide information on how to set up a VMware vsphere / vsan cluster.

In a nutshell, the installation of SAP Data Intelligence 3.3 consists of the following steps:

  • Installing VMware virtual machines in the vsphere cluster as dedicated nodes for the RKE 2 cluster

  • Creating the configuration of the vsphere CPI/CSI drivers for the use with RKE 2

  • Installing RKE 2 Kubernetes cluster on the dedicated nodes

  • Deploying SAP Data Intelligence 3.3 on RKE 2 Kubernetes cluster

  • Performing post-installation steps for SAP Data Intelligence 3.3

  • Testing the installation of SAP Data Intelligence 3.3

To have a fully supported setup, there are two Kubernetes clusters required. One runs SUSE Rancher Management server and the other runs the actual workload, which for the purpose of this guide is SAP Data Intelligence.

2 Requirements

2.1 Hardware requirements

This chapter describes the hardware requirements for installing SAP Data Intelligence 3.3 on RKE 2 on top of SUSE Linux Enterprise Server 15 SP3. Only the AMD64/Intel 64 architecture is applicable for our use case.

2.1.1 Hardware Sizing

Correct hardware sizing is very important for setting up SAP Data Intelligence 3.3 on RKE 2.

2.1.1.1 Development systems
  • Minimal hardware requirements for a generic SAP Data Intelligence 3 deployment:

    • At least 7 nodes are needed for the Kubernetes cluster.

    • Minimum sizing of the nodes needs to be as shown below:

Server RoleCountRAMCPUDisk space

Management Workstation

1

16 GiB

4

>100 GiB

Master Node

3

16 GiB

4

>120 GiB

Worker Node

4

32 GiB

8

>120 GiB

2.1.1.2 Production systems
  • Minimal hardware requirements for an SAP Data Intelligence 3 deployment for production use:

    • At least seven nodes are needed for the Kubernetes cluster.

    • Minimum sizing of the nodes needs to be as shown below:

      Server RoleCountRAMCPUDisk space

      Management Workstation

      1

      16 GiB

      4

      >100 GiB

      Master Node

      3

      16 GiB

      4

      >120 GiB

      Worker Node

      4

      64 GiB

      16

      >120 GiB

2.2 Software requirements

The following list contains the software components needed to install SAP Data Intelligence 3.3 on RKE 2:

  • SUSE Linux Enterprise Server 15 SP4

  • Rancher Kubernetes Engine 2

  • SAP Software Lifecycle Bridge

  • SAP Data Intelligence 3.3

  • Secure private registry for container images, for example https://documentation.suse.com/sbp/all/single-html/SBP-Private-Registry/index.html

  • Access to a storage solution providing dynamically physical volumes

  • If it is planned to use Vora’s streaming tables checkpoint store, an S3 bucket like object store is needed

  • If it is planned to enable backup of SAP Data Intelligence 3.3 during installation access to an S3-compatible object store is needed

3 Preparations

4 Installation of RKE 2 on top of VMware vSphere and VMware vSAN

4.1 Prerequisites:

  • A running VMware vSphere / vSAN installation.

    • NOTE: The installation of the VMware vSphere / vSAN environment is not in the scope of this document.

  • Create the virtual machines for the RKE 2 cluster with SUSE Linux Enterprise Server 15 SP4 as operating system in the vSphere environment. Make sure these virtual machines are sized according to the recommendations given above in this guide.

  • Make sure that uuid creation for disks is enabled in the settings for the virtual machines.

4.2 Install RKE 2 cluster on top of the VMware virtual machines.

Before you start the installation of RKE 2, create the configuration below for the RKE 2 cluster. This is neccessary to use the vSAN as backing storage for the storage class in RKE 2. You will need the following data:

  • user on vSphere/vSAN with the necessary access rights

  • vCenter hostname

  • datacenter ID

  • ClusterID

  • vSAN url / datastorage url

You should obtain this information from the VMware vSphere/vSAN administrator.

These data will be used to configure the helm manifests for the vsphere CPI and CSI provider and to access the resources in the vSphere installation.

To use the vSphere CPI and CSI, RKE2 must be configured to use the rancher-vsphere cloud provider.

$ sudo  mkdir -p /etc/rancher/rke2
$ sudo echo "cloud-provider-name: rancher-vsphere" > /etc/rancher/rke2/config.yaml"

This enables the deployment of the vSphere CPI and CSI from pre-packaged Helm charts in RKE 2. It will also deploy a storage class that makes use of the vSphere CPI/CSI drivers.

Create the configuration for the CPI vSphere provider Helm chart:

  • Create the directory structure on first the master node

$ sudo mkdir -p /var/lib/rancher/rke2/server/manifests
$ cd /var/lib/rancher/rke2/server/manifests

Then create the file rancher-vsphere-cpi-config.yaml in the directory.

/var/lib/rancher/rke2/server/manifests
$ cat <<EOF >
apiVersion: helm.cattle.io/v1
kind: HelmChartConfig
metadata:
  name: rancher-vsphere-cpi
  labels:
  namespace: kube-system
spec:
  valuesContent: |-
    vCenter:
      host: "vcenterhostname"
      datacenters: "datacentername"
      username: "xxxxxxxxxxx"
      password: "xxxxxxxxxxxx"
      insecure: true
      credentialsSecret:
        generate: true
    cloudControllerManager:
      nodeSelector:
        node-role.kubernetes.io/control-plane: "true"

EOF

In the same directory, the file rancher-vsphere-csi-config.yaml will be created.

$ cat <<EOF > /var/lib/rancher/rke2/server/manifests/rancher-vsphere-csi-config.yaml
apiVersion: helm.cattle.io/v1
kind: HelmChartConfig
metadata:
  name: rancher-vsphere-csi
  namespace: kube-system
spec:
  valuesContent: |-
    vCenter:
      host: "vcenter host"
      datacenters: "datacenter"
      username: "xxxxxxx"
      password: "xxxxxxxxx"
      clusterId: "vSANClusterID"
      insecure: true
      configSecret:
        configTemplate: |
         [Global]
         cluster-id = {{ required ".Values.vCenter.clusterId must be provided" (default .Values.vCenter.clusterId .Values.global.cattle.clusterId) | quote }}
         user = {{ .Values.vCenter.username | quote }}
         password = {{ .Values.vCenter.password | quote }}
         port = {{ .Values.vCenter.port | quote }}
         insecure-flag = {{ .Values.vCenter.insecureFlag | quote }}
         [VirtualCenter {{ .Values.vCenter.host | quote }}]
         datacenters = {{ .Values.vCenter.datacenters | quote }}
         [Labels]
    storageClass:
      datastoreURL: "ds:///vmfs/volumes/vsan:XXXXXXXXXXX/"
    csiController:
      nodeSelector:
        node-role.kubernetes.io/control-plane: "true"
EOF

See the RKE 2 documentation here:

Now you can deploy the RKE 2 cluster on the dedicated virtual machines.

  • Connect to the nodes dedicated as master for the RKE 2 cluster

  • Download and install RKE 2

$ export INSTALL_RKE2_TYPE=server
$ export INSTALL_RKE2_VERSION=<wanted version here>
$ curl -sfL https://get.rke2.io | sh -
$ systemctl enable --now rke2-server.service
  • Connect to the nodes dedicated as workers of the RKE 2 cluster:

$ export INSTALL_RKE2_TYPE=agent
$ export INSTALL_RKE2_VERSION=<wanted version here>
$ curl -sfL https://get.rke2.io | sh -
$ systemctl enable --now rke2-agent.service
  • More details can be found in the RKE 2 documentation:

  • https://docs.rke2.io/install/methods

  • After the deployment of the RKE 2 cluster, check the availability of the storage class vsphere-csi-sc which should have been created.

$ kubectl get sc
NAME                       PROVISIONER              RECLAIMPOLICY   VOLUMEBINDINGMODE   ALLOWVOLUMEEXPANSION   AGE
vsphere-csi-sc (default)   csi.vsphere.vmware.com   Delete          Immediate           false                  17m

Now you can proceed with installing SAP Data Intelligence.

5 Installing SAP Data Intelligence 3.3

This section describes the installation of SAP Data Intelligence 3.3 on an RKE 2-powered Kubernetes cluster.

5.1 Preparation

The following steps need to be executed before the deployment of SAP Data Intelligence 3.3 can start:

  • Create a namespace for SAP Data Intelligence 3.3.

  • Create an access to a secure private registry.

  • Download and install SAP SLC Bridge.

  • Download the stack.xml file for provisioning the DI 3.3 installation.

  • Check if the nfsd and nfsv4 kernel modules are loaded and/or loadable on the Kubernetes nodes.

5.1.1 Creating namespace for SAP Data Intelligence 3.3 in the Kubernetes cluster

Log in to your management workstation and create the namespace in the Kubernetes cluster where DI 3.3 will be deployed.

$ kubectl create ns <NAMESPACE for DI 31>
$ kubectl get ns

5.1.2 Creating cert file to access the secure private registry

Create a file named cert that contains the SSL certificate chain for the secure private registry. This imports the certificates into SAP Data Intelligence 3.3. Make sure that the file does not contain DOS-type line endings. The commands listed below will remove the DOS-type line endings and create the necessary secret.

$ cat CA.pem > cert_with_cr
$ tr -d '\r' < cert_with_cr > cert
$ kubectl -n <NAMESPACE for DI 3> create secret generic cmcertificates --from-file=cert

5.2 Downloading the SLC Bridge

The SLC Bridge can be obtained:

Download the SLC Bridge software to the management workstation.

5.3 Installing the SLC Bridge

Rename the SLC Bridge binary to slcb and make it executable. Deploy the SLC Bridge to the Kubernetes cluster.

$ mv SLCB01_XX-70003322.EXE slcb
$ chmod 0700 slcb
$ export KUBECONFIG=<KUBE_CONFIG>
$ ./slcb init

During the interactive installation, the following information is needed:

  • URL of secure private registry

  • Choose expert mode

  • Choose NodePort for the service

Take a note of the service port of the SLC Bridge. It is needed for the installation of SAP Data Intelligence 3.3 or for the reconfiguration of DI 3.3, for example to enable backup. If you forgot to note it down, the following command will list the service port:

$ kubectl -n sap-slcbridge get svc

5.4 Creating and downloading Stack XML for the SAP Data Intelligence installation

Follow the steps described in the chapter Install SAP Data Intelligence with SLC Bridge in a Cluster with Internet Access of the SAP Data Intelligence 3.3 Installation Guide.

5.4.1 Creating Stack XML

You can create the Stack XML via the SAP Maintenance Planner. Access the tool via https://support.sap.com/en/alm/solution-manager/processes-72/maintenance-planner.html. Go to the Maintenance Planner at https://apps.support.sap.com/sap/support/mp published on the SAP Web site and generate a Stack XML file with the container image definitions of the SAP Data Intelligence release that you want to install. Download the Stack XML file to a local directory. Copy stack.xml to the management workstation.

5.5 Running the installation of SAP Data Intelligence

The installation of SAP Data Intelligence 3.3 is invoked by:

$ export KUBECONFIG=<path to kubeconfig>
$ ./slcb execute --useStackXML MP_Stack_XXXXXXXXXX_XXXXXXXX_.xml --url https://<node>:<service port>/docs/index.html

This starts an interactive process for configuring and deploying SAP Data Intelligence 3.3.

The table below lists some parameters available for an SAP Data Intelligence 3.3 installation:

ParameterConditionRecommendation

Kubernetes Namespace

Always

set to namespace created beforehand

Installation Type

installation or update

either

Container Registry

Always

add the uri for the secure private registry

Checkpoint Store Configuration

installation

whether to enable Checkpoint Store

Checkpoint Store Type

if Checkpoint Store is enabled

use S3 object store from SES

Checkpoint Store Validation

if Checkpoint is enabled

Object store access will be verified

Container Registry Settings for Pipeline Modeler

optional

used if a second container registry is used

StorageClass Configuration

optional, needed if a different StorageClass is used for some components

leave the default

Default StorageClass

detected by SAP Data Intelligence installer

The Kubernetes cluster shall have a storage class annotated as default SC

Enable Kaniko Usage

optional if running on Docker

enable

Container Image Repository Settings for SAP Data Intelligence Modeler

mandatory

 

Container Registry for Pipeline Modeler

optional

Needed if a different container registry is used for the pipeline modeler images

Loading NFS Modules

optional

Make sure that nfsd and nfsv4 kernel modules are loaded on all worker nodes

Additional Installer Parameters

optional

 

For more details about input parameters for an SAP Data Intelligence 3.3 installation, visit the section Required Input Parameters of the SAP Data Intelligence Installation Guide.

5.6 Post-installation tasks

After the installation workflow is successfully finished, you need to carry out some additional tasks:

  • Obtain or create an SSL certificate to securely access the SAP Data Intelligence installation:

    • Create a certificate request using openssl, for example:

      $ openssl req -newkey rsa:2048 -keyout <hostname>.key -out <hostname>.csr
    • Decrypt the key:

      $ openssl rsa -in <hostname>.key -out decrypted-<hostname>.key
    • Let a CA sign the <hostname>.csr You will receive a <hostname>.crt.

    • Create a secret from the certificate and the key in the SAP Data Intelligence 3 namespace:

      $ export NAMESPACE=<{di} 3 namespace>
      $ kubectl -n $NAMESPACE create secret tls vsystem-tls-certs --key  decrypted-<hostname>.key--cert <hostname>.crt
  • Deploy an nginx-ingress controller:

    • For more information, see https://kubernetes.github.io/ingress-nginx/deploy/#bare-metal.

    • Create the nginx-ingress controller as a nodePort service according to the Ingress nginx documentation:

      $ kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/controller-v0.46.0/deploy/static/provider/baremetal/deploy.yaml
    • Determine the port the nginx controller is redirecting HTTPS to:

      $ kubectl -n ingress-nginx get svc ingress-nginx-controller

      The output should be similar to the below:

      kubectl -n ingress-nginx get svc ingress-nginx-controller
      NAME                       TYPE       CLUSTER-IP    EXTERNAL-IP   PORT(S)                      AGE
      ingress-nginx-controller   NodePort   10.43.86.90   <none>        80:31963/TCP,443:{di_version}06/TCP   53d

      In our example here, the TLS port is be 3.306. Note the port IP down as you will need it to access the SAP Data Intelligence installation from the outside.

  • Create an Ingress to access the SAP Data Intelligence installation:

    $ cat <<EOF > ingress.yaml
    apiVersion: extensions/v1beta1
    kind: Ingress
    metadata:
      annotations:
        kubernetes.io/ingress.class: nginx
        nginx.ingress.kubernetes.io/force-ssl-redirect: "true"
        nginx.ingress.kubernetes.io/secure-backends: "true"
        nginx.ingress.kubernetes.io/backend-protocol: HTTPS
        nginx.ingress.kubernetes.io/proxy-body-size: "0"
        nginx.ingress.kubernetes.io/proxy-buffer-size: 16k
        nginx.ingress.kubernetes.io/proxy-connect-timeout: "30"
        nginx.ingress.kubernetes.io/proxy-read-timeout: "1800"
        nginx.ingress.kubernetes.io/proxy-send-timeout: "1800"
      name: vsystem
    spec:
      rules:
      - host: "<hostname FQDN must match SSL certificate"
        http:
          paths:
          - backend:
              serviceName: vsystem
              servicePort: 8797
            path: /
      tls:
      - hosts:
        - "<hostname FQDN must match SSL certificate>"
        secretName: vsystem-tls-certs
    EOF
    $ kubectl apply -f ingress.yaml
  • Connecting to https://hostname:<ingress service port> brings up the SAP Data Intelligence login dialog.

5.7 Testing the SAP Data Intelligence 3 installation

Finally, the SAP Data Intelligence 3 installation should be verified with some very basic tests:

  • Log in to SAP Data Intelligence’s launchpad

  • Create example pipeline

  • Create ML Scenario

  • Test machine learning

  • Download vctl

For details, see the SAP Data Intelligence 3 Installation Guide

6 Maintenance tasks

This section provides some tips about what should and could be done to maintain the Kubernetes cluster, the operating system and the SAP Data Intelligence 3 deployment.

6.1 Backup

It is good practice to keep backups of all relevant data to be able to restore the environment in case of a failure. To perform regular backups, follow the instructions as outlined in the respective documentation below:

6.2 Upgrade or update

This section explains how you can keep your installation of SAP Data Intelligence, RKE 2 and SUSE Linux Enterprise Server up-to-date.

6.2.1 Updating the operating system

To obtain updates for SUSE Linux Enterprise Server 15 SP4, the installation must be registered either to SUSE Customer Center, an SMT or RMT server, or SUSE Manager with a valid subscription.

  • SUSE Linux Enterprise Server 15 SP4 can be updated on the command line using zypper:

    $ sudo zypper ref -s
    $ sudo zypper lu
    $ sudo zypper patch
  • Other methods for updating SUSE Linux Enterprise Server 15 SP4 are described in the product documentation.

If an update requires a reboot of the server, make sure that this can be done safely.

  • For example, block access to SAP Data Intelligence, and drain and cordon the Kubernetes node before rebooting:

    $ kubectl edit ingress <put in some dummy port>
    $ kubectl drain <node>
  • Check the status of the node:

    $kubectl get node <node>

    The node should be marked as not schedulable.

  • On RKE 2 master nodes, run the command:

    $ sudo systemctl stop rke2-server
  • On RKE 2 worker nodes, run the command:

    $ sudo systemctl stop rke2-agent
  • Update SUSE Linux Enterprise Server 15 SP4:

    $ ssh node
    $ sudo zypper patch
  • Reboot the nodes if necessary or start the appropriate RKE 2 service.

    • On master nodes, run the command:

      $ sudo systemctl start rke2-server
    • On worker nodes, run the command:

      $ sudo systemctl start rke2-agent
  • Check if the respective nodes are back and uncordon them.

    $ kubectl get nodes
    $ kubectl uncordon <node>

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If the Modified Version includes new front-matter sections or appendices that qualify as Secondary Sections and contain no material copied from the Document, you may at your option designate some or all of these sections as invariant. To do this, add their titles to the list of Invariant Sections in the Modified Version’s license notice. These titles must be distinct from any other section titles.

You may add a section Entitled "Endorsements", provided it contains nothing but endorsements of your Modified Version by various parties—​for example, statements of peer review or that the text has been approved by an organization as the authoritative definition of a standard.

You may add a passage of up to five words as a Front-Cover Text, and a passage of up to 25 words as a Back-Cover Text, to the end of the list of Cover Texts in the Modified Version. Only one passage of Front-Cover Text and one of Back-Cover Text may be added by (or through arrangements made by) any one entity. If the Document already includes a cover text for the same cover, previously added by you or by arrangement made by the same entity you are acting on behalf of, you may not add another; but you may replace the old one, on explicit permission from the previous publisher that added the old one.

The author(s) and publisher(s) of the Document do not by this License give permission to use their names for publicity for or to assert or imply endorsement of any Modified Version.

5. COMBINING DOCUMENTS

You may combine the Document with other documents released under this License, under the terms defined in section 4 above for modified versions, provided that you include in the combination all of the Invariant Sections of all of the original documents, unmodified, and list them all as Invariant Sections of your combined work in its license notice, and that you preserve all their Warranty Disclaimers.

The combined work need only contain one copy of this License, and multiple identical Invariant Sections may be replaced with a single copy. If there are multiple Invariant Sections with the same name but different contents, make the title of each such section unique by adding at the end of it, in parentheses, the name of the original author or publisher of that section if known, or else a unique number. Make the same adjustment to the section titles in the list of Invariant Sections in the license notice of the combined work.

In the combination, you must combine any sections Entitled "History" in the various original documents, forming one section Entitled "History"; likewise combine any sections Entitled "Acknowledgements", and any sections Entitled "Dedications". You must delete all sections Entitled "Endorsements".

6. COLLECTIONS OF DOCUMENTS

You may make a collection consisting of the Document and other documents released under this License, and replace the individual copies of this License in the various documents with a single copy that is included in the collection, provided that you follow the rules of this License for verbatim copying of each of the documents in all other respects.

You may extract a single document from such a collection, and distribute it individually under this License, provided you insert a copy of this License into the extracted document, and follow this License in all other respects regarding verbatim copying of that document.

7. AGGREGATION WITH INDEPENDENT WORKS

A compilation of the Document or its derivatives with other separate and independent documents or works, in or on a volume of a storage or distribution medium, is called an "aggregate" if the copyright resulting from the compilation is not used to limit the legal rights of the compilation’s users beyond what the individual works permit. When the Document is included in an aggregate, this License does not apply to the other works in the aggregate which are not themselves derivative works of the Document.

If the Cover Text requirement of section 3 is applicable to these copies of the Document, then if the Document is less than one half of the entire aggregate, the Document’s Cover Texts may be placed on covers that bracket the Document within the aggregate, or the electronic equivalent of covers if the Document is in electronic form. Otherwise they must appear on printed covers that bracket the whole aggregate.

8. TRANSLATION

Translation is considered a kind of modification, so you may distribute translations of the Document under the terms of section 4. Replacing Invariant Sections with translations requires special permission from their copyright holders, but you may include translations of some or all Invariant Sections in addition to the original versions of these Invariant Sections. You may include a translation of this License, and all the license notices in the Document, and any Warranty Disclaimers, provided that you also include the original English version of this License and the original versions of those notices and disclaimers. In case of a disagreement between the translation and the original version of this License or a notice or disclaimer, the original version will prevail.

If a section in the Document is Entitled "Acknowledgements", "Dedications", or "History", the requirement (section 4) to Preserve its Title (section 1) will typically require changing the actual title.

9. TERMINATION

You may not copy, modify, sublicense, or distribute the Document except as expressly provided for under this License. Any other attempt to copy, modify, sublicense or distribute the Document is void, and will automatically terminate your rights under this License. However, parties who have received copies, or rights, from you under this License will not have their licenses terminated so long as such parties remain in full compliance.

10. FUTURE REVISIONS OF THIS LICENSE

The Free Software Foundation may publish new, revised versions of the GNU Free Documentation License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. See http://www.gnu.org/copyleft/.

Each version of the License is given a distinguishing version number. If the Document specifies that a particular numbered version of this License "or any later version" applies to it, you have the option of following the terms and conditions either of that specified version or of any later version that has been published (not as a draft) by the Free Software Foundation. If the Document does not specify a version number of this License, you may choose any version ever published (not as a draft) by the Free Software Foundation.

ADDENDUM: How to use this License for your documents

Copyright (c) YEAR YOUR NAME.
   Permission is granted to copy, distribute and/or modify this document
   under the terms of the GNU Free Documentation License, Version 1.2
   or any later version published by the Free Software Foundation;
   with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
   A copy of the license is included in the section entitled “GNU
   Free Documentation License”.

If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts, replace the “ with…​Texts.” line with this:

with the Invariant Sections being LIST THEIR TITLES, with the
   Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST.

If you have Invariant Sections without Cover Texts, or some other combination of the three, merge those two alternatives to suit the situation.

If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software.