Running Percona XtraDB Cluster In A Multi-host Docker Network
Joyce Buzard
@Yamakasi, this integration is not actually part of XtraDB cluster itself. The integration between etcd and PXC is accomplished using some helper scripts. So yes, these scripts probably need an update. You can follow the instructions on the PXC docker to use this without etcd in order to get your system up and running. I highly recommend that you create a issue for our dev team on this matter.
In this blog, we are going to deploy application containers on top of a load-balanced Galera Cluster on 3 Docker hosts (docker1, docker2 and docker3), connected through an overlay network as a proof of concept for MySQL clustering in multiple Docker hosts environment. We will use Docker Engine Swarm mode as the orchestration tool.
Now we have both etcd and flannel running and it's time to start the xtradb cluster nodes which will be registering to the etcd to create the cluster on different hosts. To create the nodes run the following command on each node. It is recommended to wait for the first node to start up before you start the next nodes.
I am using a slightly modified docker percona xtradb image since the script inside which ensures if the cluster nodes are registered into etcd were not working properly so I had to fix the script for my usage. But the official image should be working as well out of the box.
As results this is a very simple way of creating a percona xtradb cluster using rkt. Of course we could use some mounted folders from the host to ensure that we don't loose any files in case the xtradb cluster goes down and the container needs to be redeployed but that is not covered into this tutorial since it's coverage inside the rkt documentation is good enough.
If a user does not want the driver to create the VLAN sub-interface, it needs toexist before running docker network create. If you have sub-interfacenaming that is not interface.vlan_id it is honored in the -o parent= optionagain as long as the interface exists and is up.
So, what happens if the switch connecting the three Docker Swarm nodes goes down? A network partition, which will split a three-node Galera Cluster into 'single-node' components. The cluster state will get demoted into Non-Primary and the Galera node state will turn to Initialized. This situation turns the containers into an unhealthy state according to the health check. After a period 600 seconds if the network is still down, those database containers will be destroyed and replaced with new containers by Docker Swarm according to the "docker service create" command. You will end up having a new cluster starting from scratch, and the existing data is removed.
SST against a large dataset (hundreds of GBytes) is no fun. Depending on the hardware, network and workload, it may take hours to complete. Server resources may be saturated during the operation. Despite throttling is supported in SST (only for xtrabackup and mariabackup) using --rlimit and --use-memory options, we are still exposed to a degraded cluster when you are running out of majority active nodes. For example, if you are unlucky enough to find yourself with only one out of three nodes running. Therefore, you are advised to perform SST during quiet hours. You can, however, avoid SST by taking some manual steps, as described in this blog post.
Here, we are going to use Weave as the Docker network plugin for multi-host networking. This is mainly due to its simplicity to get it installed and running, and support for DNS resolver (containers running under this network can resolve each other's hostname). There are two ways to get Weave running - systemd or through Docker. We are going to install it as a systemd unit, so it's independent from Docker daemon (otherwise, we would have to start Docker first before Weave gets activated).
If you enable vSphere HA on a cluster, if the TKGI Management Console appliance VM is running on a host in that cluster, and if the host reboots, vSphere HA recreates a new TKGI Management Console appliance VM on another host in the cluster. Due to an issue with vSphere HA, the ovfenv data for the newly created appliance VM is corrupted and the new appliance VM does not boot up with the correct network configuration.
Docker Compose has further simplified the development process by allowing developers to define their infrastructure, including application services, networks, and volumes, in a single file. Docker Compose offers an efficient alternative to running multiple docker container create and docker container run commands.
There are multiple ways to install the PMM client on a node and register it with PMM server. The preferred method of installing the PMM client on a node and registering it with the PMM server is to use Docker. Docker images of PMM server are stored in the percona/pmm-server public repository. Note that the host requires network access and must be capable of running Docker 1.12.6 or later.
In this article, you will learn how to create multiple Kubernetes clusters locally and establish direct communication between them with Kind and Submariner. Kind (Kubernetes in Docker) is a tool for running local Kubernetes clusters using Docker containers. Each Kubernetes node is a separated Docker container. All these containers are running in the same Docker network kind.
Our goal in this article is to establish direct communication between pods running in two different Kubernetes clusters created with Kind. Of course, it is not possible by default. We should treat such clusters as two Kubernetes clusters running in different networks. Here comes Submariner. It is a tool originally created by Rancher. It enables direct networking between pods and services in different Kubernetes clusters, either on-premises or in the cloud.
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