SAP NetWeaver Enqueue Replication 1 High Availability Cluster - SAP NetWeaver 7.40 and 7.50 #

This guide details how to:

This guide focuses on the high availability of the central services.

For SAP HANA system replication, follow the guides for the performance- or cost-optimized scenario.

This guide describes how to set up a pacemaker cluster using SUSE Linux Enterprise Server for SAP Applications 12 for the Enqueue Replication scenario. The goal is to match the SAP NW-HA-CLU 7.40 certification specifications and goals.

These goals include:

The updated certification SAP NW-HA-CLU 7.40 has redefined some of the test procedures and described new expectations how the cluster should behave in special conditions. These changes allowed us to improve the cluster architecture and to design it for easier usage and setup.

Shared SAP resources are on a central NFS server.

The SAP instances themselves are installed on a shared disk to allow switching over the file systems for proper functionality. The second need for a shared disk is that we are using the SBD for the cluster fencing mechanism STONITH.

3.2 Three systems for ASCS, ERS, database and additional SAP instances #

 

This guide describes the installation of a distributed SAP system on three systems. In this setup, only two systems are in the cluster. The database and SAP dialog instances could also be added to the cluster by either adding the third node to the cluster or by installing the database on either of the nodes. However we recommend to install the database on a separate cluster.

Note

The cluster in this guide only manages the SAP instances ASCS and ERS, because of the focus of the SAP NW-HA-CLU 7.40 certification.

If your database is SAP HANA, we recommend to set up the performance optimized system replication scenario using our automation solution SAPHanaSR. The SAPHanaSR automation should be set up in an own two node cluster. The setup is described in a separate best practices document available at http://documentation.suse.com/sbp/sap.

Figure 1: Three systems for the certification setup #

 

Clustered machines #

 

• one machine (hacert01) for ASCS

  • Hostname: sapha1as

• one machine (hacert02) for ERS

  • Hostname: sapha1er

Non-Clustered machine #

 

• one machine (hacert03) for DB and DI

  • Hostname: sapha1db

  • Hostname: sapha1d1

  • Hostname: sapha1d2

3.3 High availability for the database #

 

Depending on your needs you can also increase the availability of the database if your database is not already highly available by design.

3.3.1 SAP HANA system replication #

 

A perfect enhancement of the three node scenario described in this document is to implement an SAP HANA system replication (SR) automation.

Figure 2: One cluster for central services, one for SAP HANA SR #

 

The following Databases are supported in combination with this scenario:

• SAP HANA DATABASE 1.0

• SAP HANA DATABASE 2.0

3.3.2 Simple stack #

 

Another option is to implement a second cluster for a database without SR aka "ANYDB". The cluster resource agent SAPDatabase uses the SAPHOSTAGENT to control and monitor the database.

Figure 3: One cluster for the central services and one cluster for the ANY database #

 

Table 1: The following OS / Databases combination are examples for this scenario #

 

SUSE Linux Enterprise Server for SAP Applications 12
Intel X86_64	POWER LITTLE ENDIAN
SAP HANA DATABASE 1.0
SAP HANA DATABASE 2.0	SAP HANA DATABASE 2.0
DB2 FOR LUW 10.5
MaxDB 7.9
ORACLE 12.1
SAP ASE 16.0 FOR BUS. SUITE

Note

First version for SAP NetWeaver on Power Little Endian is 7.50. More information about supported combination of OS and Databases for SAP NetWeaver can be found at the SAP Product Availability Matrix. (SAP PAM)

3.4 Integration of SAP NetWeaver into the cluster using the Cluster Connector #

 

The integration of the HA cluster through the SAP control framework using the sap_suse_cluster_connector is of special interest. The sapstartsrv controls SAP instances since SAP Kernel versions 6.40. One of the classical problems running SAP instances in a highly available environment is the following: If an SAP administrator changes the status (start/stop) of an SAP instance without using the interfaces provided by the cluster software, the cluster framework will detect that as an error status and will bring the SAP instance into the old status by either starting or stopping the SAP instance. This can result in very dangerous situations if the cluster changes the status of an SAP instance during some SAP maintenance tasks. This new updated solution enables the central component sapstartsrv to report state changes to the cluster software, and therefore avoids the previously described dangerous situations. (See also blog article "Using sap_vendor_cluster_connector for interaction between cluster framework and sapstartsrv") (https://blogs.sap.com/2014/05/08/using-sapvendorclusterconnector-for-interaction-between-cluster-framework-and-sapstartsrv/comment-page-1/).

Figure 4: Cluster connector to integrate the cluster with the SAP start framework #

 

Note

For this scenario we are using an updated version of the sap-suse-cluster-connector. This version implements the API version 3 for the communication between the cluster framework and the sapstartsrv.

The new version of the sap-suse-cluster-connector now allows to start, stop and 'move' an SAP instance. The integration between the cluster software and the sapstartsrv also implements the option to run checks of the HA setup using either the command line tool sapcontrol or the SAP management consoles (SAP MMC or SAP MC).

3.5 Disks and partitions #

 

For all SAP file systems beside the file systems on NFS we are using XFS.

3.5.1 Shared disk for cluster ASCS and ERS #

 

The disk for the ASCS and ERS instances need to be shared and assigned to the cluster nodes hacert01 and hacert02. Beside the partitions for the file systems for the SAP instances the disk also provides the partition to be used as SBD.

On hacert01 prepare the file systems for the shared disk. Create three partitions on the shared drive /dev/sdb:

• partition one (/dev/sdb1) for SBD (7M)

• partition two (/dev/sdb2) for the first file system (10GB) formatted with XFS

• partition three (/dev/sdb3) for the second file system (10GB) formatted with XFS

You could either use YaST to create partitions or using available command line tools. The following script could be used for non-interactive setups.

# parted -s /dev/sdb print
# # we are on the 'correct' drive, right?
# parted -s /dev/sdb mklabel gpt
# parted -s /dev/sdb mkpart primary 1049k 8388k
# parted -s /dev/sdb mkpart primary 8389k 10.7G
# parted -s /dev/sdb mkpart primary 10.7G 21.5G
# mkfs.xfs /dev/sdb2
# mkfs.xfs /dev/sdb3

For these file systems we recommend to use plain partitions to keep the cluster configuration as easy as possible. However you could also place these file systems in separate volume groups. In that case you need to add further cluster resources to control the logical volume groups. This is out of the scope of this setup guide.

After we have partitioned the shared disk on hacert01 we need to request a partition table rescan on hacert02.

# partprobe; fdisk -l /dev/sdb

During the SAP installation we need /usr/sap/HA1/ASCS00 to be mounted on hacert01 and /usr/sap/HA1/ERS10 to be mounted on hacert02.

• hacert01: /dev/sdb2 /usr/sap/HA1/ASCS00

• hacert02: /dev/sdb3 /usr/sap/HA1/ERS10

3.5.2 Disk for DB and cialog instances (MaxDB Example) #

 

The disk for the database and primary application server is assigned to hacert03. In an advanced setup this disk should be shared between hacert03 and an optional additional node building an own cluster.

• partition one (/dev/sdb1) for SBD (7M) - not used here but a reservation for an optional second cluster

• partition two (/dev/sdb2) for the Database (60GB) formatted with XFS

• partition three (/dev/sdb3) for the second file system (10GB) formatted with XFS

• partition four (/dev/sdb4) for the third file system (10GB) formatted with XFS

You could either use YaST to create partitions or using available command line tools. The following script could be used for non-interactive setups.

# parted -s /dev/sdb print
# # we are on the 'correct' drive, right?
# parted -s /dev/sdb mklabel gpt
# parted -s /dev/sdb mkpart primary 1049k 8388k
# parted -s /dev/sdb mkpart primary 8389k 60G
# parted -s /dev/sdb mkpart primary 60G 70G
# parted -s /dev/sdb mkpart primary 70G 80G
# mkfs.xfs /dev/sdb2
# mkfs.xfs /dev/sdb3
# mkfs.xfs /dev/sdb4

To be mounted either by OS or an optional cluster #

 

• hacert03: /dev/sdb2 /sapdb

• hacert03: /dev/sdb3 /usr/sap/HA1/DVEBMGS01

• hacert03: /dev/sdb4 /usr/sap/HA1/D02

Note

D01 ⇒ Since NetWeaver 7.5, the primary application server instance directory has been renamed. (D<Instance_Number>)

NFS server #

 

• nfs1:/data/nfs/suseEnqReplNW7x/HA1/sapmnt /sapmnt

• nfs1:/data/nfs/suseEnqReplNW7x/HA1/usrsapsys /usr/sap/HA1/SYS

Media #

 

• nfs1:/data/SCT/media/SAP-MEDIA/NW74 /sapcd

or

• nfs1:/data/SCT/media/SAP-MEDIA/NW75 /sapcd

192.168.201.111  hacert01
192.168.201.112  hacert02
192.168.201.113  hacert03
192.168.201.115  sapha1as
192.168.201.116  sapha1er
192.168.201.117  sapha1db
192.168.201.118  sapha1d1
192.168.201.119  sapha1d2

3.7 Mount points and NFS shares #

 

In our setup the directory /usr/sap is part of the root file system. You could of course also create a dedicated file system for that area and mount /usr/sap during the system boot. As /usr/sap also contains the SAP control file sapservices and the saphostagent, the directory should not be placed on a shared file system between the cluster nodes.

We need to create the directory structure on all nodes which might be able to run the SAP resource. The SYS directory will be on an NFS share for all nodes.

• Creating mount points and mounting NFS share on all nodes

Example 1: SAP NetWeaver 7.4 #

 

# mkdir -p /sapcd
# mkdir -p /sapmnt
# mkdir -p /usr/sap/HA1/{ASCS00,D02,DVEBMGS01,ERS10,SYS}
# mount -t nfs nfs1:/data/nfs/suseEnqReplNW7x/HA1/sapmnt    /sapmnt
# mount -t nfs nfs1:/data/nfs/suseEnqReplNW7x/HA1/usrsapsys /usr/sap/HA1/SYS
# mount -t nfs nfs1:/data/SCT/media/SAP-MEDIA/NW74 /sapcd

Example 2: SAP NetWeaver 7.5 #

 

# mkdir -p /sapcd
# mkdir -p /sapmnt
# mkdir -p /usr/sap/HA1/{ASCS00,D01,D02,ERS10,SYS}
# mount -t nfs nfs1:/data/nfs/suseEnqReplNW7x/HA1/sapmnt    /sapmnt
# mount -t nfs nfs1:/data/nfs/suseEnqReplNW7x/HA1/usrsapsys /usr/sap/HA1/SYS
# mount -t nfs nfs1:/data/SCT/media/SAP-MEDIA/NW75 /sapcd

• Only MaxDB: creating mount points for the database at hacert03:

# mkdir -p /sapdb

• Only HANA: creating mount points for database at hacert03:

# mkdir -p /hana/{shared,data,log}

• Other databases: creating mount points based on there installation guide.

As we do not control the NFS shares via the cluster in this setup, you should add these file systems to /etc/fstab to get the file systems mounted during the next system boot.

Figure 5: File system layout including NFS shares #

 

We prepare the three servers for the distributed SAP installation. Server 1 (hacert01) will be used to install the ASCS SAP instance. Server 2 (hacert02) will be used to install the ERS SAP instance. Server 3 (hacert03) will be used to install the dialog SAP instances and the database.

• Mounting the instance and database file systems at one specific node:

Example 3: SAP NetWeaver 7.40 on x86_64 architecture with MaxDB #

 

(ASCS   hacert01) # mount /dev/sdb2 /usr/sap/HA1/ASCS00
(ERS    hacert02) # mount /dev/sdb3 /usr/sap/HA1/ERS10
(DB     hacert03) # mount /dev/sdb2 /sapdb
(Dialog hacert03) # mount /dev/sdb3 /usr/sap/HA1/DVEBMGS01
(Dialog hacert03) # mount /dev/sdb4 /usr/sap/HA1/D02

Example 4: SAP NetWeaver 7.50 on PowerLE architecture with HANA #

 

(ASCS   hacert01) # mount /dev/sdb2 /usr/sap/HA1/ASCS00
(ERS    hacert02) # mount /dev/sdb3 /usr/sap/HA1/ERS10
(DB     hacert03) # mount /dev/sdc1 /hana/shared
(DB     hacert03) # mount /dev/sdc2 /hana/log
(DB     hacert03) # mount /dev/sdc3 /hana/data
(Dialog hacert03) # mount /dev/sdb3 /usr/sap/HA1/D01
(Dialog hacert03) # mount /dev/sdb4 /usr/sap/HA1/D02

• As a result the directory /usr/sap/HA1/ should now look like:

# ls -la /usr/sap/HA1/
total 0
drwxr-xr-x 1 ha1adm sapsys 70 28. Mar 17:26 ./
drwxr-xr-x 1 root   sapsys 58 28. Mar 16:49 ../
drwxr-xr-x 7 ha1adm sapsys 58 28. Mar 16:49 ASCS00/
drwxr-xr-x 1 ha1adm sapsys  0 28. Mar 15:59 D02/
drwxr-xr-x 1 ha1adm sapsys  0 28. Mar 15:59 D01/
drwxr-xr-x 1 ha1adm sapsys  0 28. Mar 15:59 ERS10/
drwxr-xr-x 5 ha1adm sapsys 87 28. Mar 17:21 SYS/

Note

The owner of the directory and files is changed during the SAP installation. By default all of them are owned by root.

The overall procedure to install the distributed SAP is:

The result will be a distributed SAP installation as illustrated here:

Figure 6: Distributed installation of the SAP system #

 

Group sapinst      1000
Group sapsys       1001
Group sapadm       3000
Group sdba         3002

User  ha1adm       3000
User  sdb          3002
User  sqdha1       3003
User  sapadm       3004
User  h04adm       4001

# ip a a 192.168.201.115/24 dev eth0
# mount /dev/sdb2 /usr/sap/HA1/ASCS00
# cd /sapcd/SWPM/
# ./sapinst SAPINST_USE_HOSTNAME=sapha1as

# ip a a 192.168.201.116/24 dev eth0
# mount /dev/sdb3 /usr/sap/HA1/ERS10
# cd /sapcd/SWPM/
# ./sapinst SAPINST_USE_HOSTNAME=sapha1er

# chown -R ha1adm:sapsys /usr/sap/HA1/ERS10

# sapcontrol -nr 00 -function Stop    # to stop the ASCS
# sapcontrol -nr 00 -function Start   # to start the ASCS

4.4 Poststeps for ASCS and ERS #

 

4.4.1 Stopping ASCS and ERS #

 

On hacert01

# su - ha1adm
# sapcontrol -nr 00 -function Stop
# sapcontrol -nr 00 -function StopService

On hacert02

# su - ha1adm
# sapcontrol -nr 10 -function Stop
# sapcontrol -nr 10 -function StopService

4.4.2 Maintaining sapservices #

 

Ensure /usr/sap/sapservices hold both entries (ASCS+ERS) on both cluster nodes. This allows the sapstartsrv clients to start the service like (do not execute this at this point in time).

As user ha1adm

# sapcontrol -nr 10 -function StartService HA1

The /usr/sap/sapservices looks like (typically one line per instance):

#!/bin/sh
LD_LIBRARY_PATH=/usr/sap/HA1/ASCS00/exe:$LD_LIBRARY_PATH; export LD_LIBRARY_PATH; /usr/sap/HA1/ASCS00/exe/sapstartsrv pf=/usr/sap/HA1/SYS/profile/HA1_ASCS00_sapha1as -D -u ha1adm
LD_LIBRARY_PATH=/usr/sap/HA1/ERS10/exe:$LD_LIBRARY_PATH; export LD_LIBRARY_PATH; /usr/sap/HA1/ERS10/exe/sapstartsrv pf=/usr/sap/HA1/ERS10/profile/HA1_ERS10_sapha1er -D -u ha1adm

4.4.3 Integrating the cluster framework using sap-suse-cluster-connector #

 

Install the package sap-suse-cluster-connector version 3.1.0 from our repositories:

# zypper in sap-suse-cluster-connector

Note

Be careful there are two packages available. The package sap_suse_cluster_connector continues to contain the old version 1.1.0 (SAP API 1). The package sap-suse-cluster-connector contains the new version 3.1.x (SAP API 3). The package sap-suse-cluster-connector with version 3.1.x implements the SUSE SAP API version 3. New features like SAP Rolling Kernel Switch (RKS) and the migration of ASCS are only supported with this new version.

For the ERS and ASCS instance edit the instance profiles HA1_ASCS00_sapha1as and HA1_ERS10_sapha1er in the profile directory /usr/sap/HA1/SYS/profile/.

You need to tell the sapstartsrv to load the HA script connector library and to use the sap-suse-cluster-connector. Additionally, make sure the feature Autostart is not used.

service/halib = $(DIR_EXECUTABLE)/saphascriptco.so
service/halib_cluster_connector = /usr/bin/sap_suse_cluster_connector

Add the user ha1adm to the unix user group haclient.

# usermod -aG haclient ha1adm

4.4.4 Adapting SAP profiles to match the SAP NW-HA-CLU 7.40 certification #

 

For the ASCS, change the start command from Restart_Program_xx to Start_Program_xx for the enqueue server (enserver). This change tells the SAP start framework not to self-restart the enqueue process. Such a restart would lead in loss of the locks.

Example 5: File /usr/sap/HA1/SYS/profile/HA1_ASCS00_sapha1as #

 

Start_Program_01 = local $(_EN) pf=$(_PF)

Optionally you could limit the number of restarts of services (in the case of ASCS this limits the restart of the message server).

For the ERS change instance the start command from Restart_Program_xx to Start_Program_xx for the enqueue replication server (enrepserver).

Example 6: File /usr/sap/HA1/SYS/profile/HA1_ERS10_sapha1er #

 

Start_Program_00 = local $(_ER) pf=$(_PFL) NR=$(SCSID)

4.4.5 Starting ASCS and ERS #

 

On hacert01

# su - ha1adm
# sapcontrol -nr 00 -function StartService HA1
# sapcontrol -nr 00 -function Start

On hacert02

# su - ha1adm
# sapcontrol -nr 10 -function StartService HA1
# sapcontrol -nr 10 -function Start

# ip a a 192.168.201.117/24 dev eth0
# mount /dev/sdb2 /sapdb
# cd /sapcd/SWPM/
# ./sapinst SAPINST_USE_HOSTNAME=sapha1db

# ip a a 192.168.201.117/24 dev eth0
# mount /dev/sdc1 /hana/shared
# mount /dev/sdc2 /hana/log
# mount /dev/sdc3 /hana/data
# cd /sapcd/SWPM/
# ./sapinst SAPINST_USE_HOSTNAME=sapha1db

# ip a a 192.168.201.118/24 dev eth0
# mount /dev/sdb3 /usr/sap/HA1/DVEBMGS01
# cd /sapcd/SWPM/
# ./sapinst SAPINST_USE_HOSTNAME=sapha1d1

# ip a a 192.168.201.118/24 dev eth0
# mount /dev/sdb3 /usr/sap/HA1/D01
# cd /sapcd/SWPM/
# ./sapinst SAPINST_USE_HOSTNAME=sapha1d1

# ip a a 192.168.201.119/24 dev eth0
# mount /dev/sdb4 /usr/sap/HA1/D02
# cd /sapcd/SWPM/
# ./sapinst SAPINST_USE_HOSTNAME=sapha1d2

The main procedure to implement the cluster is as follows:

Note

Before we continue to set up the cluster, we first stop all SAP instances, remove the (manual added) IP addresses on the cluster nodes and unmount the file systems which will be controlled by the cluster later.

Note

The SBD device/partition need to be created in beforehand. In this setup guide we already have reserved partition /dev/sdb1 for SBD usage.

# zypper in -t pattern ha_sles

# modprobe softdog
# echo "softdog" > /etc/modules-load.d/softdog.conf
# systemctl enable sbd
# ha-cluster-init -y -i eth0 -u -s /dev/sdb1

# modprobe softdog
# echo "softdog" > /etc/modules-load.d/softdog.conf
# systemctl enable sbd
# rsync 192.168.201.111:/etc/sysconfig/sbd /etc/sysconfig

# ha-cluster-join -y -c 192.168.201.111 -i eth0

Last updated: Thu Nov 21 14:25:53 2019		Last change: Thu Nov 21 14:23:21 2019 by ha1adm via crm_resource on hacert01
Stack: corosync
Current DC: hacert01 (version 1.1.19-20181105.ccd6b5b10) - partition with quorum
2 nodes and 1 resource configured

Online: [ hacert01 hacert02 ]

stonith-sbd	(stonith:external/sbd):	Started hacert01

# crm configure show
...
property cib-bootstrap-options: \
        have-watchdog=true \
        dc-version=1.1.19-20181105.ccd6b5b10 \
        cluster-infrastructure=corosync \
        cluster-name=hacluster \
        stonith-enabled=true \
        last-lrm-refresh=1494346532
rsc_defaults rsc-options: \
        resource-stickiness=1 \
        migration-threshold=3
op_defaults op-options: \
        timeout=600 \
        record-pending=true

5.2 Configuring cluster resources #

 

We need a changed SAPInstance resource agent for SAP NetWeaver to not use the master-slave construct anymore and to move to a more cluster-like construct to start and stop the ASCS and the ERS itself and not only the complete master-slave.

For this there is a new functionality for the ASCS needed to follow the ERS. The ASCS needs to mount the shared memory table of the ERS to avoid the loss of locks.

Figure 7: Resources and constraints #

 

The implementation is done using the new flag "runs_ers_$SID" within the RA, enabled with help of the resource parameter "IS_ERS=TRUE".

Another benefit of this concept is that we can now work with local (mountable) file systems instead of a shared (NFS) file system for the SAP instance directories.

5.2.1 Preparing the cluster for adding the resources #

 

To avoid that the cluster starts partially defined resources, we set the cluster to the maintenance mode. This deactivates all monitor actions.

As user root

# crm configure property maintenance-mode="true"

5.2.2 Configuring the resources for the ASCS #

 

First we configure the resources for the file system, IP address and the SAP instance. Of course you need to adapt the parameters to your environment.

Example 7: ASCS primitive #

 

primitive rsc_fs_HA1_ASCS00 Filesystem \
  params device="/dev/sdb2" directory="/usr/sap/HA1/ASCS00" \
     fstype=xfs \
  op start timeout=60s interval=0 \
  op stop timeout=60s interval=0 \
  op monitor interval=20s timeout=40s
primitive rsc_ip_HA1_ASCS00 IPaddr2 \
  params ip=192.168.201.115 \
  op monitor interval=10s timeout=20s
primitive rsc_sap_HA1_ASCS00 SAPInstance \
  operations $id=rsc_sap_HA1_ASCS00-operations \
  op monitor interval=11 timeout=60 on-fail=restart \
  params InstanceName=HA1_ASCS00_sapha1as \
     START_PROFILE="/sapmnt/HA1/profile/HA1_ASCS00_sapha1as" \
     AUTOMATIC_RECOVER=false \
  meta resource-stickiness=5000 failure-timeout=60 \
     migration-threshold=1 priority=10

Example 8: ASCS group #

 

group grp_HA1_ASCS00 \
  rsc_ip_HA1_ASCS00 rsc_fs_HA1_ASCS00 rsc_sap_HA1_ASCS00 \
     meta resource-stickiness=3000

Create a txt file (like crm_ascs.txt) with your preferred text editor, enter both examples (primitives and group) to that file and load the configuration to the cluster manager configuration.

As user root

# crm configure load update crm_ascs.txt

5.2.3 Configuring the resources for the ERS #

 

Second, we configure the resources for the file system, IP address and the SAP instance. Of course you need to adapt the parameters to your environment.

The specific parameter IS_ERS=true should only be set for the ERS instance.

Example 9: ERS primitive #

 

primitive rsc_fs_HA1_ERS10 Filesystem \
  params device="/dev/sdb3" directory="/usr/sap/HA1/ERS10" fstype=xfs \
  op start timeout=60s interval=0 \
  op stop timeout=60s interval=0 \
  op monitor interval=20s timeout=40s
primitive rsc_ip_HA1_ERS10 IPaddr2 \
  params ip=192.168.201.116 \
  op monitor interval=10s timeout=20s
primitive rsc_sap_HA1_ERS10 SAPInstance \
  operations $id=rsc_sap_HA1_ERS10-operations \
  op monitor interval=11 timeout=60 on-fail=restart \
  params InstanceName=HA1_ERS10_sapha1er \
     START_PROFILE="/sapmnt/HA1/profile/HA1_ERS10_sapha1er" \
     AUTOMATIC_RECOVER=false IS_ERS=true \
  meta priority=1000

Example 10: ERS group #

 

group grp_HA1_ERS10 \
  rsc_ip_HA1_ERS10 rsc_fs_HA1_ERS10 rsc_sap_HA1_ERS10

Create a txt file (like crm_ers.txt) with your preferred text editor, enter both examples (primitives and group) to that file and load the configuration to the cluster manager configuration.

As user root

# crm configure load update crm_ers.txt

5.2.4 Configuring the colocation constraints between ASCS and ERS #

 

The constraints between the ASCS and ERS instance are needed to define that the ASCS instance starts exactly on the cluster node running the ERS instance after a failure (loc_sap_HA1_failover_to_ers). This constraint is needed to ensure that the locks are not lost after an ASCS instance (or node) failure.

If the ASCS instance has been started by the cluster the ERS instance should be moved to an "other" cluster node (col_sap_HA1_no_both). This constraint is needed to ensure that the ERS will synchronize the locks again and the cluster is ready for an additional take-over.

Example 11: Location constraint #

 

colocation col_sap_HA1_no_both -5000: grp_HA1_ERS10 grp_HA1_ASCS00
location loc_sap_HA1_failover_to_ers rsc_sap_HA1_ASCS00 \
         rule 2000: runs_ers_HA1 eq 1
order ord_sap_HA1_first_start_ascs Optional: rsc_sap_HA1_ASCS00:start \
      rsc_sap_HA1_ERS10:stop symmetrical=false

Create a txt file (like crm_col.txt) with your preferred text editor, enter all three constraints to that file and load the configuration to the cluster manager configuration.

As user root

# crm configure load update crm_col.txt

5.2.5 Activating the cluster #

 

Now the last step is to end the cluster maintenance mode and to allow the cluster to detect already running resources.

As user root

# crm configure property maintenance-mode="false"

For more information, see the documents listed below.

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Copyright © 2000, 2001, 2002 Free Software Foundation, Inc. 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed.

The purpose of this License is to make a manual, textbook, or other functional and useful document "free" in the sense of freedom: to assure everyone the effective freedom to copy and redistribute it, with or without modifying it, either commercially or noncommercially. Secondarily, this License preserves for the author and publisher a way to get credit for their work, while not being considered responsible for modifications made by others.

This License is a kind of "copyleft", which means that derivative works of the document must themselves be free in the same sense. It complements the GNU General Public License, which is a copyleft license designed for free software.

We have designed this License in order to use it for manuals for free software, because free software needs free documentation: a free program should come with manuals providing the same freedoms that the software does. But this License is not limited to software manuals; it can be used for any textual work, regardless of subject matter or whether it is published as a printed book. We recommend this License principally for works whose purpose is instruction or reference.

This License applies to any manual or other work, in any medium, that contains a notice placed by the copyright holder saying it can be distributed under the terms of this License. Such a notice grants a world-wide, royalty-free license, unlimited in duration, to use that work under the conditions stated herein. The "Document", below, refers to any such manual or work. Any member of the public is a licensee, and is addressed as "you". You accept the license if you copy, modify or distribute the work in a way requiring permission under copyright law.

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The "Invariant Sections" are certain Secondary Sections whose titles are designated, as being those of Invariant Sections, in the notice that says that the Document is released under this License. If a section does not fit the above definition of Secondary then it is not allowed to be designated as Invariant. The Document may contain zero Invariant Sections. If the Document does not identify any Invariant Sections then there are none.

The "Cover Texts" are certain short passages of text that are listed, as Front-Cover Texts or Back-Cover Texts, in the notice that says that the Document is released under this License. A Front-Cover Text may be at most 5 words, and a Back-Cover Text may be at most 25 words.

A "Transparent" copy of the Document means a machine-readable copy, represented in a format whose specification is available to the general public, that is suitable for revising the document straightforwardly with generic text editors or (for images composed of pixels) generic paint programs or (for drawings) some widely available drawing editor, and that is suitable for input to text formatters or for automatic translation to a variety of formats suitable for input to text formatters. A copy made in an otherwise Transparent file format whose markup, or absence of markup, has been arranged to thwart or discourage subsequent modification by readers is not Transparent. An image format is not Transparent if used for any substantial amount of text. A copy that is not "Transparent" is called "Opaque".

Examples of suitable formats for Transparent copies include plain ASCII without markup, Texinfo input format, LaTeX input format, SGML or XML using a publicly available DTD, and standard-conforming simple HTML, PostScript or PDF designed for human modification. Examples of transparent image formats include PNG, XCF and JPG. Opaque formats include proprietary formats that can be read and edited only by proprietary word processors, SGML or XML for which the DTD and/or processing tools are not generally available, and the machine-generated HTML, PostScript or PDF produced by some word processors for output purposes only.

The "Title Page" means, for a printed book, the title page itself, plus such following pages as are needed to hold, legibly, the material this License requires to appear in the title page. For works in formats which do not have any title page as such, "Title Page" means the text near the most prominent appearance of the work’s title, preceding the beginning of the body of the text.

A section "Entitled XYZ" means a named subunit of the Document whose title either is precisely XYZ or contains XYZ in parentheses following text that translates XYZ in another language. (Here XYZ stands for a specific section name mentioned below, such as "Acknowledgements", "Dedications", "Endorsements", or "History".) To "Preserve the Title" of such a section when you modify the Document means that it remains a section "Entitled XYZ" according to this definition.

The Document may include Warranty Disclaimers next to the notice which states that this License applies to the Document. These Warranty Disclaimers are considered to be included by reference in this License, but only as regards disclaiming warranties: any other implication that these Warranty Disclaimers may have is void and has no effect on the meaning of this License.

You may copy and distribute the Document in any medium, either commercially or noncommercially, provided that this License, the copyright notices, and the license notice saying this License applies to the Document are reproduced in all copies, and that you add no other conditions whatsoever to those of this License. You may not use technical measures to obstruct or control the reading or further copying of the copies you make or distribute. However, you may accept compensation in exchange for copies. If you distribute a large enough number of copies you must also follow the conditions in section 3.

You may also lend copies, under the same conditions stated above, and you may publicly display copies.

If you publish printed copies (or copies in media that commonly have printed covers) of the Document, numbering more than 100, and the Document’s license notice requires Cover Texts, you must enclose the copies in covers that carry, clearly and legibly, all these Cover Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on the back cover. Both covers must also clearly and legibly identify you as the publisher of these copies. The front cover must present the full title with all words of the title equally prominent and visible. You may add other material on the covers in addition. Copying with changes limited to the covers, as long as they preserve the title of the Document and satisfy these conditions, can be treated as verbatim copying in other respects.

If the required texts for either cover are too voluminous to fit legibly, you should put the first ones listed (as many as fit reasonably) on the actual cover, and continue the rest onto adjacent pages.

If you publish or distribute Opaque copies of the Document numbering more than 100, you must either include a machine-readable Transparent copy along with each Opaque copy, or state in or with each Opaque copy a computer-network location from which the general network-using public has access to download using public-standard network protocols a complete Transparent copy of the Document, free of added material. If you use the latter option, you must take reasonably prudent steps, when you begin distribution of Opaque copies in quantity, to ensure that this Transparent copy will remain thus accessible at the stated location until at least one year after the last time you distribute an Opaque copy (directly or through your agents or retailers) of that edition to the public.

It is requested, but not required, that you contact the authors of the Document well before redistributing any large number of copies, to give them a chance to provide you with an updated version of the Document.

You may copy and distribute a Modified Version of the Document under the conditions of sections 2 and 3 above, provided that you release the Modified Version under precisely this License, with the Modified Version filling the role of the Document, thus licensing distribution and modification of the Modified Version to whoever possesses a copy of it. In addition, you must do these things in the Modified Version:

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.

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".

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.

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.

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.

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.

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.

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.