Re: Is there a way to find out if a server is part of application connection string?

[Miles Garnsey]

Could you maybe do something with the output of  lsof -nPi? It'll give you
open network connections across the system. You could then filter them down
using grep/awk for just those accessing Cassandra's CQL port (9042 by
default).

On Wed, Jun 7, 2023 at 10:10 AM Surbhi Gupta 
wrote:

> Hi,
>
> We have a cluster with many applications connecting to it.
> We need to decommission few of the servers from the cluster .
> Without asking the application team, is there any way to know the ips
> of the application connection string?
> Does cassandra logs (system or debug) this information somewhere?
>
> Application team might have different ips than seed nodes.
>
> Thanks in advance.
> Surbhi
>

Re: Seed List

[Miles Garnsey]

From my understanding, the main thing to be aware of is that Cassandra’s 
default SeedProvider doesn't resolve multiple A records, so you’re actually 
limited in terms of the load balancing/DNS configurations you can use.

You can however write alternative seed providers which have different (perhaps 
more appropriate) behaviour, see here 

 for an example.


> On 23 Jun 2022, at 10:53 pm, Durity, Sean R  
> wrote:
> 
> It can work to use host names. We have done it for temporary clusters where 
> there is at least a theoretical possibility of an ip address change. I don't 
> know all the trade-offs of using host names, since we don't do that for 
> production.
> 
> 
> Sean R. Durity
> 
> 
> INTERNAL USE
> 
> -Original Message-
> From: Marc Hoppins  
> Sent: Thursday, June 23, 2022 3:33 AM
> To: user@cassandra.apache.org
> Subject: [EXTERNAL] Seed List
> 
> Hi guys,
> 
> Documentation (for almost everything) uses IP addresses for seeds,  is it 
> possible to use the FQDN instead for the seeds (cass.yaml)?  It is far easier 
> to read/use names.
> 
> Thanks
> 
> M

Re: Cassandra Management tools?

[Miles Garnsey]

A cheeky plug for the project I’m currently working on: k8ssandra-operator 
 aims to automate a lot of 
everyday Cassandra maintenance tasks by orchestrating Cassandra on Kubernetes. 
We offer integration with the TLP projects Reaper (repair), Medusa (backup + 
restore), as well as MCAC (monitoring via Prometheus and Grafana). We also 
offer support for the essentials - upgrades, scaling, automated health checking 
and restarts of failed instances.

We hit 1.0.0 12 days ago, so the project is very dynamic and is under active 
development. We’re still figuring a lot of things out, but - if we do our job 
right - we think that k8ssandra-operator will become the preferred way to 
manage Cassandra in modern environments over time.

https://github.com/k8ssandra/k8ssandra-operator 
 


> On 2 Mar 2022, at 6:22 am, Jeff Jirsa  wrote:
> 
> Most teams are either using things like ansible/python scripts, or have 
> bespoke infrastructure. 
> 
> Some of what you're describing is included in the intent of the 
> `cassandra-sidecar` project: 
> https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=95652224 
> 
> 
> 
> Goals
> We target two main goals for the first version of the sidecar, both work 
> towards having a easy to use control plane for managing Cassandra’s data 
> plane.
> Provide an extensible and pluggable architecture for developers and operators 
> to easily operate Cassandra as well as easing integration with their existing 
> infrastructure. One major sub-goal of this goal is:
> The proposal should pass the “curl test”: meaning that it is accessible to 
> standard tooling and out of the box libraries available for practically every 
> environment or programming language (including python, ruby, bash). This 
> means that as a public interface we cannot choose Java specific (jmx) or 
> Cassandra specific (CQL) APIs.
> Provide basic but essential and useful functionality. Some proposed scope in 
> this document:
> Run health checks on replicas and the cluster
> Run diagnostic commands on individual nodes as well as all nodes in the 
> cluster (bulk commands)
> Export metrics via pluggable agents rather than polling JMX
> Schedule periodic management activities such as running clean ups
> (as a stretch goal) safely restart all nodes in the cluster.
> 
> 
> The health checker seems to be implemented, I'm not sure if the coordinated 
> cleanup or similar exist yet (or if there are JIRAs around for them). In 
> theory, this type of work - outside the database, in automation - should be 
> really easy for newcomers who are solving their own problems. 
> 
> Other things that sorta fall into this space, but may be not quite what 
> you're looking for:
> 
> - https://github.com/Netflix/Priam  (if you 
> run very much like netflix runs, especially on AWS)
> - https://github.com/thelastpickle/cassandra-reaper 
>  for the repair automation
> - https://github.com/JeremyGrosser/tablesnap 
>  (old-ish, for backups)
> 
> 
> 
> On Tue, Mar 1, 2022 at 11:05 AM Joe Obernberger  > wrote:
> Thanks all - I'll take a look at Ansible.  Back in my Hadoop days, we 
> would use Cloudera manager (course that now costs $). Sounds like we 
> need a new open source project!  :)
> 
> -Joe
> 
> On 3/1/2022 7:46 AM, Bowen Song wrote:
> > We use Ansible to manage a fairly large (200+ nodes) cluster. We 
> > created our own Ansible playbooks for common tasks, such as rolling 
> > restart. We also use Cassandra Reaper for scheduling and running 
> > repairs on the same cluster. We occasionally also use pssh (parallel 
> > SSH) for inspecting the logs or configurations on selected nodes. 
> > Running pssh on very larger number of servers is obviously not 
> > practical due the the available screen space constraint.
> >
> > On 28/02/2022 21:59, Joe Obernberger wrote:
> >> Hi all - curious what tools are folks using to manage large Cassandra 
> >> clusters?  For example, to do tasks such as nodetool cleanup after a 
> >> node or nodes are added to the cluster, or simply rolling start/stops 
> >> after an update to the config or a new version?
> >> We've used puppet before; is that what other folks are using?
> >> Thanks for any suggestions.
> >>
> >> -Joe
> >>
> >