Category Archives: Real Application Cluster

Parameter REMOTE_LISTENER pointing to a TNS alias? Beware of how it registers.

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On an Oracle Database instance, if I set:

The instance tries to resolve the cluster-scan name to detect if it is a SCAN address.
So, after it solves, it stores all the addresses it gets and registers to them.
I can check which addresses there are with this query:

In this case, the instance registers to the three addresses discovered, which is OK: all three SCAN listeners will get service updates from the instance.

But if I have this TNS alias:

and I set:

I get:

the result is that the instance registers only at the first IP fot from the DNS, leaving the other SCANs without the service registration and thus random

This is in my opinion quite annoying, as my goal here was to have all the DBs set with:

in order to facilitate changes of ports, database migrations from different clusters, clones, etc.

So the solution is either to revert to the syntax “cluster-scan:port”, or specifying explicitly all the endpoints in the address list:

I am sure it is “working as designed”, but I wonder if it could be an enhancement to have the address expended fully also in case of TNS alias….
Or… do you know any way to do it from a TNS alias without having the full IP list?

Cheers

—

Ludo

FPP local-mode: Steps to remove/add node from a cluster if RHP fails to move gihome

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I am getting more and more experience with patching clusters with the local-mode automaton. The whole process would be very complex, but the local-mode automaton makes it really easy.

I have had nevertheless a couple of clusters where the process did not work:

#1: The very first cluster that I installed in 18c

This cluster has “kind of failed” patching the first node. Actually, the rhpctl command exited with an error:

But actually, the helper kept running and configured everything properly:

The cluster was OK on the first node, with the correct patch level. The second node, however, was failing with:

I am not sure about the cause, but let’s assume it is irrelevant for the moment.

#2: A cluster with new GI home not properly linked with RAC

This was another funny case, where the first node patched successfully, but the second one failed upgrading in the middle of the process with a java NullPointer exception. We did a few bad tries of prePatch and postPatch to solve, but after that the second node of the cluster was in an inconsistent state: in ROLLING_UPGRADE mode and not possible to patch anymore.

Common solution: removing the node from the cluster and adding it back

In both cases we were in the following situation:

  • one node was successfully patched to 18.6
  • one node was not patched and was not possible to patch it anymore (at least without heavy interventions)

So, for me, the easiest solution has been removing the failing node and adding it back with the new patched version.

Steps to remove the node

Although the steps are described here: https://docs.oracle.com/en/database/oracle/oracle-database/18/cwadd/adding-and-deleting-cluster-nodes.html#GUID-8ADA9667-EC27-4EF9-9F34-C8F65A757F2A, there are a few differences that I will highlight:

Stop of the cluster:

The actual procedure to remove a node asks to deconfigure the databases and managed homes from the active cluster version. But as we manage our homes with golden images, we do not need this; we rather want to keep all the entries in the OCR so that when we add it back, everything is in place.

Once stopped the CRS, we have deinstalled the CRS home on the failing node:

This  complained about the CRS that was down, but it continued and ask for this script to be executed:

We’ve got errors also for this script, but the remove process was OK afterall.

Then, from the surviving node:

Adding the node back

From the surviving node, we ran gridSetup.sh and followed the steps to ad the node.

Wait before running root.sh.

In our case, we have originally installed the cluster starting with a SW_ONLY install. This type of installation keeps some leftovers in the configuration files that prevent the root.sh from configuring the cluster…we have had to modify rootconfig.sh:

then, after running root.sh and the config tools, everything was back as before removing the node form the cluster.

For one of the clusters , both nodes were at the same patch level, but the cluster was still in ROLLING_PATCH mode. So we have had to do a

—

Ludo

Oracle SW_ONLY install leads to relink with rac_off at every attachHome

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OK, I really do not know what other title I should use for this post.

I have developed and presented a few times my personal approach to Oracle Home provisioning and patching. You can read more in this series.

With this approach:

  • I install the software (either GI or RDBMS) with the option SW_ONLY once
  • I patch it to the last version
  • I create a golden image that I evolve for the rest of the release lifecycle

When I need to install it, I just unzip the golden image and attach it to the Central Inventory.

I have discovered quite longtime ago that, every time I was attaching the home to the inventory, the binaries were relinked with rac_off, disregarding the fact that the home that I zipped actually had RAC enabled. This is quite annoying at my work at CERN, as all our databases are RAC.

So my solution to the problem is to detect if the server is on a cluster, and relink on the fly:

This is a simplified snippet of my actual code, but it gives the idea.

What causes the relink with rac_off?

I have discovered recently that the steps used by the runInstaller process to attach the Oracle Home are described in this file:

and in my case, for all my golden images, it contains:

So, it does not matter how I prepare my images: unless I change this file and put rac_on, the runInstaller keeps relinking with rac_off.

I have thought about changing the file, but then realized that I prefer to check and recompile at runtime, so I can reuse my images also for standalone servers (in case we need them).

Just to avoid surprises, it is convenient to check if a ORACLE_HOME is linked with RAC with this small function:

This is true especially for Grid Infrastructure golden images, as they have the very same behavior of RDBMS homes, with the exception that they might break out-of-place patching if RAC is not enabled: the second ASM instance will not mount because the first will be exclusively mounted without the RAC option.

 

HTH.

—

Ludovico

Oracle Grid Infrastructure 19c does not configure FPP in local-mode by default. How to add it?

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I have been installing Grid Infrastructure 18c for a while, then switched to 19c when it became GA.

At the beginning I have been overly enthusiast by the shorter installation time:

The GIMR is now optional, that means that deciding to install it is a choice of the customer, and a customer might like to keep it or not, depending on its practices.

Not having the GIMR by default means not having the local-mode automaton. This is also not a problem at all. The default configuration is good for most customers and works really well.

This new simplified configuration reduces some maintenance effort at the beginning, but personally I use a lot the local-mode automaton for out-of-place patching of Grid Infrastructure (read my blog posts to know why I really love the local-mode automaton), so it is something that I definitely need in my clusters.

A choice that makes sense for Oracle and most customers

Oracle vision regarding Grid Infrastructure consists of a central management of clusters, using the Oracle Domain Services Cluster. In this kind of deployment, the Management Repository, TFA, and many other services, are centralized. All the clusters use those services remotely instead of having them configured locally. The local-mode automaton is no exception: the full, enterprise-grade version of Fleet Patching and Provisioning (FPP, formerly Rapid home provisioning or RHP) allows much more than just out-of-place patching of Grid Infrastructure, so it makes perfectly sense to avoid those configurations everywhere, if you use a Domain Cluster architecture. Read more here.

Again, as I said many times in the past, doing out-of-place patching is the best approach in my opinion, but if you keep doing in-place patching, not having the local-mode automaton is not a problem at all and the default behavior in 19c is a good thing for you.

I need local-mode automaton on 19c, what I need to do at install time?

If you have many clusters, you are not installing them by hand with the graphic interface (hopefully!). In the responseFile for 19c Grid Infrastructure installation, this is all you need to change comparing to a 18c:

as you can see, also Flex ASM is not part of the game by default in 19c.

Once you specify in the responseFile that you want GIMR, then the local-mode automaton is installed  as well by default.

I installed GI 19c without GIMR and local-mode automaton. How can I add them to my new cluster?

First, recreate the empty MGMTDB CDB by hand:

Then, configure the PDB for the cluster. Pay attention to the -local switch that is not documented (or at least it does not appear in the inline help):

After that, you might check that you have the PDB for your cluster inside the MGMTDB, I’ll skip this step.

Before creating the rhpserver (local-mode automaton resource), we need the volume and filesystem to make it work (read here for more information).

The volume:

The filesystem:

Finally, create the local-mode automaton resource:

Again, note that there is a -local switch that is not documented. Specifying it will create the resource as a local-mode automaton and not as a full FPP Server (or RHP Server, damn, this change of name gets me mad when I write blog posts about it 🙂 ).

HTH

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Ludovico

Oracle Clusterware Services Status at a glance, fast!

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If you use Oracle Clusterware or you deploy your databases to the Oracle Cloud, you probably have some application services defined with srvctl for your database.

If you have many databases, services and nodes, it might be annoying, when doing maintenance or service relocation, to have a quick overview about how services are distributed across the nodes and what’s their status.

With srvctl (the official tool for that), it is a per-database operation:

If you have many databases, you have to run db by db.

It is also slow! For example, this database has 20 services. Getting the status takes 27 seconds:

Instead of operating row-by-row (get the status for each service), why not relying on the cluster resources with crsctl and get the big picture once?

crsctl stat res -f  returns a list of ATTRIBUTE_NAME=value for each service, eventually more than one if the service is not singleton/single instance  but uniform/multi instance.

By parsing them with some awk code can provide nice results!

STATE, INTERNAL_STATE and TARGET are useful in this case and might be used to display colours as well.

  • Green: Status ONLINE, Target ONLINE, STABLE
  • Black: Status OFFLINE, Target OFFLNE, STABLE
  • Red: Status ONLINE, Target OFFLINE, STABLE
  • Yellow: all other cases

Here’s the code:

Here’s what you can expect, for 92 services distributed on 4 nodes and a dozen of databases (the output is snipped and the names are masked):

I’d be curious to know if it works well for your environment, please comment here. 🙂

Thanks

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Ludo

Oracle Grid Infrastructure 18c patching part 3: Executing out-of-place patching with the local-mode automaton

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I wish I had more time to blog in the recent weeks. Sorry for the delay in this blog series 🙂

If you have not read the two previous blog posts, please do it now. I suppose here that you have the Independent Local-Mode Automaton already enabled.

What does the Independent Local-mode Automaton?

The automaton automates the process of moving the active Grid Infrastructure Oracle Home from the current one to a new one. The new one can be either at a higher patch level or at a lower one. Of course, you will probably want to patch your grid infrastructure, going then to a higher level of patching.

Preparing the new Grid Infrastructure Oracle Home

The GI home, starting from 12.2, is just a zip that is extracted directly in the new Oracle Home. In this blog post I suppose that you want to patch your Grid Infrastructure from an existing 18.3 to a brand new 18.4 (18.5 will be released very soon).

So, if your current OH is /u01/app/grid/crs1830, you might want to prepare the new home in /u01/app/grid/crs1840 by unzipping the software and then patching using the steps described here.

If you already have a golden image with the correct version, you can unzip it directly.

Beware of four important things: 

  1. You have to register the new Oracle home in the Central Inventory using the SW_ONLY install, as  described here.
  2. You must do it for all the nodes in the cluster prior to upgrading
  3. The response file must contain the same groups (DBA, OPER, etc) as the current active Home, otherwise errors will appear.
  4. You must relink by hand your Oracle binaries with the RAC option:
    $ cd /u01/app/grid/1crs1840/rdbms/lib
    $ make -f ins_rdbms.mk rac_on ioracle

In fact, after every attach to the central inventory the binaries are relinked without RAC option, so it is important to activate RAC again to avoid bad problems when upgrading the ASM with the new Automaton.

Executing the move gihome

If everything is correct, you should have now the current and new Oracle Homes, correctly registered in the Central Inventory, with the RAC option activated.

You can now do a first eval to check if everything looks good:

My personal suggestion at least at your first experiences with the automaton, is to move the Oracle Home on one node at a time. This way, YOU control the relocation of the services and resources before doing the actual move operation.

Here is the execution for the first node:

From this output you can see at line 15 that the cluster status is NORMAL, then the cluster is stopped on node 1 (lines 16 to 100), then the active version is modified in the oracle-ohasd.service file (line 101), then started back with the new version (lines 102 to 171). The cluster status now is ROLLING PATCH (line 172). The TFA and the node list are updated. 

Before continuing with the other(s) node(s), make sure that all the resources are up & running:

You might want as well to relocate manually your resources back to node 1 prior to continuing on node 2.

After that, node 2 can follow the very same procedure:

As you can see, there are two differencse here: the second node was in this case the last one, so the cluster status gets back to NORMAL, and the GIMR is patched with datapatch (lines 176-227).

At this point, the cluster has been patched. After some testing, you can safely remove the inactive version of Grid Infrastructure using the deinstall binary ($OLD_OH/deinstall/deinstall).

Quite easy, huh?

If you combine the Independent Local-mode Automaton with a home-developed solution for the creation and the provisioning of Grid Infrastructure Golden Images, you can easily achieve automated Grid Infrastructure patching of a big, multi-cluster environment.

Of course, Fleet Patching and Provisioning remains the Rolls-Royce: if you can afford it, GI patching and much more is completely automated and developed by Oracle, so you will have no headaches when new versions are released. But the local-mode automaton might be enough for your needs.

— 

Ludo

Oracle Grid Infrastructure 18c patching part 2: Independent Local-mode Automaton architecture and activation

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The first important step before starting using the new Independent Local-mode Automaton is understanding which are its components inside a cluster.

Resources

Here’s the list of service that you will find when you install a Grid Infrastructure 18c:

As you can see, there are 4 components that are OFFLINE by default:

Three local resources (that are present on each node):

  • ora.MGMT.GHCHKPT.advm
  • ora.mgmt.ghchkpt.acfs
  • ora.helper

One cluster resource (active on only one server at a time, it can relocate):

  • ora.rhpserver

If you have ever worked with 12c Rapid Home Provisioning, those name should sound familiar.

The GHCHKPT filesystem (ant its relative volume), is used to store some data regarding the ongoing operations across the cluster during the GI home move.

The ora.helper is the process that actually does the operations. It is local because each node needs it to execute some actions at some point.

The rhpserver is the server process that coordinates the operations and delegates them to the helpers.

All those services compose the independent local-mode automaton, that is the default deployment. The full RHP framework (RHP Server and RHP Client) might be configured instead with some additional work.

Important note: Just a few weeks ago Oracle changed the name of Rapid Home Provisioning (RHP) to Fleet Patching and Provisioning (FPP). The name is definitely more appealing now, but it generates again some confusion about product names and acronyms, so beware that in this series sometimes I refer to RHP, sometimes to FPP, but actually it is the same thing.

Tomcat?

You might have noticed that tomcat is deployed now in the GI home, as there are patches specific to it (here I paste the 18.4 version):

 

Indeed Tomcat is registered in the inventory and patched just like any other product inside the OH:

 

Out of the box, Tomcat is used for the Quality of Services Management (ora.qosmserver resource):

But it is used for the Independent Local Mode Automaton as well, when it is started.

Enabling and starting the independent local-mode automaton

The resources are started using the following commands (as root, the order is quite important):

Before continuing with the rhpserver resource, you might want to check if the filesystem is mounted:

Now the rhpserver should start without problems, as oracle:

Please note that if you omit to activate the filesystem first, the rhpserver will fail to start.

As you can see, now both rhpserver and the helper are online:

Now all is set to start using it!

We’ll see how to use it in the next posts.

—

Ludo

 

Oracle Grid Infrastructure 18c patching part 1: Some history

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Down the memory lane

Although sometimes I think I have been working with Oracle Grid Infrastructure since it exists, sometimes my memory does not work well. I still like to go through the Oracle RAC family history from time to time:

  • 8i -> no Oracle cluster did exist. RAC was leveraging 3rd party clusters (like Tru Cluster, AIX HACMP, Sun Cluster)…
  • 9i -> if I remember well, Oracle hired some developers of Tru Cluster after the acquisition of Compaq by HP. Oracle CRS was born and was quite similar to Tru Cluster. (The commands were almost the same: crs_stat instead of caa_stat, etc)
  • 10g -> Oracle re-branded CRS to Clusterware
  • 11g -> With the addition of ASM (and other components), Oracle created the concept of “Grid Infrastructure”, composed by Clusterware and additional products. All the new versions still use the name Grid Infrastructure and new products have been added through the years (ACFS, RHP, QoS …)

But I have missing souvenirs. For example, I cannot remember having ever upgraded an Oracle Cluster from 9i to 10g or from 10g to 11g. At that time I was working for several customers, and every new release was installed on new Hardware.

My first, real upgrade (as far as I can remember) was from 11gR2 to 12c, where the upgrade process was a nice, OUI-driven, out-of-place install.

The process was (still is 🙂 ) nice and smooth:

  • The installer copies, prepares and links the binaries on all the nodes in a new Oracle Home
  • The upgrade process is rolling: the first node puts the cluster in upgrade mode
  • The last node does the final steps and exists the cluster from the upgrade mode.

This is about Upgrading to a new release. But what about patching?

In-place patching

Patching of Grid Infrastructure has always been in-place and, I will not hide it, quite painful.

If you wanted to patch a Grid Infrastructure before release 12cR2, you had to:

  • read the documentation carefully and check for possible conflicts
  • backup the Grid Home
  • copy the patch on the host
  • evacuate all the services and databases from the cluster node that you want to patch
  • patch the binaries (depending on the versions and patches, this might be easy with opatchauto or quite painful with manual unlocking/locking and manual opatch steps)
  • restart/relocate the services back on the node
  • repeat the tasks for every node

The disadvantages of in-place patching are many:

  • Need to stage the patch on every node
  • Need to repeat the patching process for every node
  • No easy rollback (some bad problems might lead to deconfiguring the cluster from one node and then adding it back to the cluster)

Out-of-place patching

Out-of-place patching is proven to be much a better solution. I am doing it regularly since a while for Oracle Database homes and I am very satisfied with it. I am implementing it at CERN as well, and it will unlock new levels of server consolidation 🙂

I have written a blog series here, and presented about it a few times.

But out-of-place patching for Grid Infrastructure is VERY recent.

12cR2: opatchauto 

Oracle 12cR2 introduced out-of-place patching as a new feature of opatchauto.

This MOS document explains it quite in detail:

Grid Infrastructure Out of Place ( OOP ) Patching using opatchauto (Doc ID 2419319.1)

The process is the following:

  • a preparation process clones the active Oracle Home on the current node and patches it
  • a switch process switches the active Oracle Home from the old one to the prepared clone
  • those two phases are repeated for each node

12cr2-oop

The good thing is that the preparation can be done in advance on all the nodes and the switch can be triggered only if all the clones are patched successfully.

However, the staging of the patch, the cloning and patching must still happen on every node, making the concept of golden images quite useless for patching.

It is worth to mention, at this point, that Grid Infrastructure Golden Images ARE A THING, and that they have been introduced by Rapid Home Provisioning release 12cR2, where cluster automatic provisioning has been included as a new feature.

This Grid Infrastructure golden images have already been mentioned here and here.

I have discussed about Rapid Home provisioning itself here, but I will ad a couple of thoughts in the next paragraph.

18c and the brand new Independent local-mode Automaton

I have been early tester of the Rapid Home Provisioning product, when it has been released with Oracle 12.1.0.2. I have presented about it at UKOUG and as a RAC SIG webinar.
https://www.youtube.com/watch?v=vaB4RWjYPq0
https://www.ludovicocaldara.net/dba/rhp-presentation/

I liked the product A LOT, despite a few bugs due to the initial release. The concept of out-of-placing patching that RHP uses is the best one, in my opinion, to cope with frequent patches and upgrades.

Now, with Oracle 18c, the Rapid Home Provisioning Independent Local-mode Automaton comes to play. There is not that much documentation about it, even in the Oracle documentation, but a few things are clear:

  • The Independent local-mode automaton comes without additional licenses as it is not part of the RHP Server/Client infrastructure
  • It is 100% local to the cluster where it is used
  • Its main “job” is to allow moving Grid Infrastructure Homes from a non-patched version to an out-of-place patched one.

I will not disclore more here, as the rest of this blog series is focused on this new product 🙂

Stay tuned for details, examples and feedback from its usage at CERN 😉

—

Ludo

Port conflict with “Oracle Remote Method Invocation (ORMI)” during Grid Infrastructure install

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After years of installing Grid Infrastructures, today I have got for the first time an error on something new:

Looking at the logs (which I do not have now as I removed them as part of the failed install cleanup 🙁 ), the error is generated by the cluster verification utility (CVU) on this check:

The components verified by the CVU can be found inside $ORACLE_HOME/cv/cvdata/. In my case, precisely:

This check is critical, so the install fails.

In my case the port was used by mcollectived.

The port has been taken dynamically, and previous runs of CVU did not encounter the problem.

A rare port conflict that might happen when configuring GI 🙂

—

Ludo

Grid Infrastructure 18c: changes in gridSetup.sh -applyRU and -createGoldImage

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Starting with release 12cR2, Grid Infrastructure binaries are no more shipped as an installer, but as a zip file that is uncompressed directly in the Oracle Home path.
This opened a few new possibilities including patching the software before the Grid Infrastructure configuration.
My former colleague Markus Flechtner wrote an excellent blog post about it, here: https://www.markusdba.net/?p=294

Now, with 18c, there are a couple of things that changed comparing to Markus blog.

The -applyRU switch replaces the -applyPSU

While it is possible to apply several sub-patches of a PSU one by one:

it was possible to do all at once with:

Now the switch is called, for consistency with the patch naming, -applyRU.

E.g.:

Still there are no options to avoid the run of the Setup Wizard, but it is safe to ignore the error as the patch has been applied successfully.

The -createGoldImage does not work anymore if the Home is not attached

I have tried to create the golden image as per Markus post, but I get this error:

To workaround the issue, there are two ways:

  1. Create a zip file manually, as all the content needed to install the patched version is right there. No need to touch anything as the software is not configured yet.
  2. Configure the software with CRS_SWONLY before creating the gold image:

 

HTH

—

Ludo