Stavros, You need to use a Virtual IP Address (or the built in MySQL HA in Cloudstack) to point all management servers to a single MySQL instance. If the primary fails, you use the above methods with some health checking to move the VIP (or let ACS Mgmt handle it via the MySQL connector) to the redundant MySQL server.
This can be achieve with Keepalived, with a MySQL health check. I will point out that in 4.7.x and probably in 4.8, the ACS MySQL HA functionality (using the MySQL Java Connector) seems to be broken. We are currently digging into it. It's also possible to use a MySQL Active/Active Cluster via Galera. There are a bunch of people doing this, although it can increase the complexity of the install, so make sure you have really high quality health checking in case something goes south. Here is the current list of DB HA possibilities: https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=34838207 If you do deploy multiple active management servers, you'll need to put a load balancer (such as HAPROXY) in front of the servers. Here is a port list of what you need to be load balancing for a multiple management servers configuration: http://docs.cloudstack.apache.org/projects/cloudstack-administration/en/4.6/reliability.html - Si ________________________________________ From: Stavros Konstantaras <[email protected]> Sent: Monday, February 29, 2016 5:16 AM To: [email protected] Subject: Re: Management server + MySQL server requirements Hi Simon, Your proposal is correct,I currently have the recommended setup: 2 machines with nice amount of cores and RAM, with management server and mysql installed. Usage server is not currently used, BUT we do use MySQL replication for some form of HA. However, the drawback that I see is that the management server on the second head node must be down otherwise it causes the replication to fail pretty quickly. So in case of failure of the first head node the admin needs to login to the second head node and initiate the management server (or maybe you can script it and automate this). Last requirement needed is a script that automates MySQL backups (crontab can be used for that). Kind Regards Stavros > On 28 Feb 2016, at 00:06, Simon Weller <[email protected]> wrote: > > Josh, > > Unless you plan to create a massive cloud, there is probably no reason to > separate MySQL from the management server. It would actually be better to > deploy two management servers and then replicate MySQL over to the second > server for some form of HA. > > You don't really need SSDs. A couple of 10/15K SAS/SATA drives will be fine. > Most of the space allocate is for the MySQL databases. If you plan to use the > usage service, the stats collection will require more drive space. This is > configured as a separate MySQL database. > > I'd suggest you deploy a minimum of 16GB of RAM and 8 cores or so. If you > plan to grow the deployment rapidly, leave some empty memory slots for the > future. > > - Si > > ________________________________________ > From: Josh Davis <[email protected]> > Sent: Saturday, February 27, 2016 10:37 AM > To: [email protected] > Subject: Management server + MySQL server requirements > > Hi all, apologies for the spam. > This is the hardware suggestion for MySQL on the management server node. I'm > looking at a separate server for MySQL DB. > Is the bulk of the 250GB requirement used by the management server or the > MySQL DB? Do I need to use SSDs or is SAS or even SATA fine for the > management server? Can I place the MySQL DB on a VM as well?Is the MySQL > server supposed to be public facing?Is it sufficient to only connect to the > management network? No need to access the storage or guest network? > "The machines that will run the Management Server and MySQL database must > meet the following requirements. The same machines can also be used to > provide primary and secondary storage, such as via localdisk or NFS. The > Management Server may be placed on a virtual machine.Operating > system:Preferred: CentOS/RHEL 6.3+ or Ubuntu 12.04(.1)64-bit x86 CPU (more > cores results in better performance)4 GB of memory250 GB of local disk (more > results in better capability; 500 GB recommended)At least 1 NICStatically > allocated IP addressFully qualified domain name as returned by the hostname > command" > Thanks!Josh
