Three servers are used to deploy redis cluster, and three masters and three slaves are deployed in a cross-deployment method. One master and another server are deployed on one server. There is no problem in using the cluster normally, and the master and slave will be crossed. However, if a server is directly shut down and reconnected, there may be two masters on one server, or two slaves on one server. Is there any way to avoid it?
I would like to have a high-availability/redundant installation of Zookeeper running in my production environment. The problem is that I only have 2 physical frames available, so that rules out configuring a Zookeeper cluster/ensemble since I'd only have redundancy if the frame with the minority of servers goes down. What is the best practice in this situation? Is it possible to have a separate standalone install running on each frame connected to the same set of SOLR nodes or to use one server as primary and one as backup?
Zookeeper requires 3 nodes. In your scenario if you cannot get another machine you can setup multiple zookeeper nodes on the same machine in different directories using different ports.
I just investigate DC/OS, I find that DC/OS has three roles:master, slave, slave_public, I want to deploy a cluster which can host master, slave or slave_public roles on one host, but currently I can't do that.
I want to know that why can't put them on one host when designed. If I do that, could I get some suggestions?
I just have the idea. If I can't do, I'll quit using DCOS, I'll use mesos and marathon.
Is there someone has the idea with me? I look forward to the reply.
This is by design, and things are actually being worked on to re-enforce that an machine is installed with only one role because things break with more than one.
If you're trying to demo / experiment with DC/OS and you only have one machine, you can use Virtual Machines or Docker to partition that one machine into multiple machines / parts which you can install DC/OS on. dcos-vagrant and dcos-docker can help you there.
As far as installing though, the configuration for each of the three roles is incompatible with one another. The "master" role causes a whole bunch of pieces of software to be started / installed on a host (Mesos-DNS, Mesos master, marathon, exhibitor, zookeeper, 3dt, adminrouter, rexray, spartan, navstar among others) which listen on various ports. The "slave" role causes a machine to have a mesos-agent (mesos renamed mesos-slave to mesos-agent, hence the disconnect) configured and started on the agent. The mesos-agent is configured to control / most ports greater than 1024 to tasks which are launched by mesos frameworks on the agent. Several of those ports are used by services which are run on masters, resulting in odd conflicts and hard to fix bad behavior.
In the case of running the "slave" and "slave_public" on the same host, those two conflict more directly, because both of them cause mesos-agent to be run on the host, with slightly different configuration. Both the mesos-agent (the one configured with the "slave" role and the one with the "slave_public" role are configured to listen on port 5051. Only one of them can use it though, so you end up with one of the agents being non-functional.
DC/OS only supports running a node as either a master or an agent(slave). You are correct that Mesos does not have this limitation. But DC/OS is more than just a Mesos/Marathon. To enable all the additional features of DC/OS there are various components built around Mesos and Marathon. At times these components behave differently whether they are running on a master or an agent and at other times the components that exist on a master may or may not exist on an agent or vice versa. So running a master and an agent on the same node would lead to conflicts/issues.
If you are looking to run a small development setup before scaling the solution out to a bigger distributed system DC/OS Vagrant might be a good starting point.
I've been doing some experiments with Apache Ignite and I've started to look into WAN replication. By this I mean there would be 2 (or more) data centres each running an Ignite cluster. There would be some caches that I would like kept in sync between the two data centres.
Does Apache Ignite support this? If so how is this configured as I can't find any mention of this in the documentation.
At the moment Ignite does not support caches spanning multiple clusters(nor cache mirroring). If however you mean there is only one Ignite cluster consisting of nodes located in different data centers(WAN),that would be possible though would most likely be inefficient! since you will have to use the Replicated Mode.
GridGain provides asynchronous WAN replication on top of Ignite as part of their payed solution: https://www.gridgain.com/docs/latest/administrators-guide/data-center-replication/configuring-replication
I'm using Redis as a caching system on the client windows endpoint. I want to use two simultaneous caching streams where one is lru enabled and the other is disabled.
How do I run two different configs on the same instance?
Ended up using two instances with aof
OK so talked to people at Redis. It's not possible as all the configuration is global for the instance.
So the only solution is to have two different instances