I usually use Munin as monitoring software, but this (as others software I presume) needs an IP to make the ICMP or whatever pings to collect data.
In Amazon EC2 instances are created on the fly, with IP's you don't know.
How can they be monitored ?
I was thinking about using amazon console commands to read the IP's of the instances up, and change the monit configuration file on the fly also , but it can be too complicated ... or not?
Any other solution / suggestion ?
Thank you
I use revealcloud to monitor my amazon instances. You can install it once and create an ami from that systen, or bootstrap the install command if that's your method. Since the install is just one command, it's easy enough to put into the rc.local (or similar). You can then see all the instances in the dashboard or topiew as soon as they boot up.
Our instances are bootstrapped using chef recipes, so it's easier for me to provide IPs/hosts as they (= all members of my cluster) get entered into /etc/hosts on start-up. Generally, it doesn't hurt to use elastic IPs for a master server and allow all connections (in /etc/munin/munin.conf by default).
I'd solve the security 'question' on the security groups level. E.g. allow only instances with a certain security group to connect to the munin-node process (on port 4949). The question which remains is.
E.g., using ec2-authorize you can achieve
ec2-authorize mygroup -o monitorgroup -u <AWS-USER-ID>
This means that all instances with group monitorgroup can access resources on instances with mygroup.
Let me know if this helps!
If your Munin master and nodes are all hosted on EC2 than it's better to use internal hosts like domU-00-00-00-00-00-00.compute-1.internal. because this way you don't have to deal with IP addresses and security groups.
You also have to set this in /etc/munin/munin-node.conf:
allow ^.*$
You can read more about it in Monitoring AWS Ubuntu Instances using Munin
But if your Munin master is not on EC2 your best bet is to attach Elastic IP to your EC2 instance.
Related
I need to get Dmgr host and port dynamically to sync the node.
AdminControl.getHost() and AdminControl.getPort()
I am not sure whether i works. Thanks in advance
Would something like this work instead at the end of your administrative script?
AdminConfig.save()
if (NDInstall == "ND"):
nodeSync = AdminControl.completeObjectName("type=NodeSync,node=" + nodeLongName + ",*")
AdminControl.invoke(nodeSync, "sync")
A save and sync by itself doesn't require nodes or application servers to be down. Depending on the nature of the change you may need to recycle application servers to bring the change into effect. One feature that's in ND to help with high availability is the ability to ripple start servers in a cluster. This way one or more application servers stay up to service requests while a change is 'rippled' into effect.
A cluster is also an administrative unit that can be stopped and started. You can arrange your clusters however you want across your nodes.
Problem: I want to cache user information such that all my applications can read the data quickly, but I want only one specific application to be able to write to this cache.
I am on AWS, so one solution that occurred to me was a version of memcached with two ports: one port that accepts read commands only and one that accepts reads and writes. I could then use security groups to control access.
Since I'm on AWS, if there are solutions that use out-of-the box memcached or redis, that'd be great.
I suggest you use ElastiCache with one open port at 11211(Memcached)then create an EC2 instance, set your security group so only this server can access to your ElastiCache cluster. Use this server to filter your applications, so only one specific application can write to it. You control the access with security group, script or iptable. If you are not using VPC, then you can use cache security group.
I believe you can accomplish this using Redis (instead of Memcached) which is also available via ElastiCache. Once the instance has been created, you will want to create a replication group and associate it to the cache cluster you already launched.
You can then add instances to the replication group. Instances within the replication group are simply replicated from the Master Cache Cluster (single Redis instance) and so are (by default) read-only.
So, in this setup, you have a master node (single endpoint) that you can write to and as many read nodes (multiple endpoints) as you would like.
You can take security a step further and assign different routing rules to the replication group (via the VPC) so the applications reading data does not have access to the master node (the only one that can write data).
I am very new to the Amazon AWS services. I was wondering if there is a way to run an instance of EC2 (say, Amazon Linux AMI) and then connect two environments to this instance.
Particularly, I'd like to run a PHP and a Tomcat environment on a single EC2 instance.
The problem is, every time I create a new environment in Elastic Beanstalk, it seems to create a new EC2 instance as well. Am I missing something here?
I'd appreciate any hint on this.
AWS Elastic Beanstalk is designed for deploying your running apps in a way that is designed for scalability from the ground-up. Because of this, Elastic Beanstalk will launch one or more EC2 instances, connect them to an Elastic Load Balancer instance, configure CloudWatch monitoring and Auto Scaling triggers.
Also, because of its fundamental design for scalability, Elastic Beanstalk is designed around a one-app-per-environment model (whereby "environment", I mean one of these EC2 + ELB + CloudWatch + AutoScaling clusters).
Since running two separate web servers with two separate apps (PHP & Java) is not a fundamentally scalable design, it's not a use-case that Elastic Beanstalk is optimized for.
You are free to spin-up a standalone EC2 instance and install whatever you'd like on it, but you're right — git aws.push support has not been made available for standalone EC2 instances. If the git support is important to you, you'll need to weigh the pros and cons of each approach.
I would also like to be able to do this, basically from a cost perspective for demos etc.
For example, a single instance with one PHP app and one Java app. Or, a single instance with two Java apps.
However, from what I have read so far in the Elastic Beanstalk developer guide, I have not found anything explicitly stating that multiple applications per environment is supported (or even, multiple environments per EC2 instance - if that even makes sense).
It makes me wonder if this is a feature that is often requested and planned for the future, or alternatively if the single-app-per-environment model is 'by design' for some reason.
When autoscaling my EC2 instances for application, what is the best way to keep every instances in sync?
For example, there are custom settings and application files like below...
Apache httpd.conf
php.ini
PHP source for my application
To get my autoscaling working, all of these must be configured same in each EC2 instances, and I want to know the best practice to sync these elements.
You could use a private AMI which contains scripts that install software or checkout the code from SVN, etc.. The second possibility to use a deployment framework like chef or puppet.
The way this works with Amazon EC2 is that you can pass user-data to each instance -- generally a script of some sort to run commands, e.g. for bootstrapping. As far as I can see CreateLaunchConfiguration allows you to define that as well.
If running this yourself is too much of an obstacle, I'd recommend a service like:
scalarium
rightscale
scalr (also opensource)
They all offer some form of scaling.
HTH
I am planning to deploy my web app to EC2. I have several webserver instances. I have 1 primary database instance. I have 1 failover database instance. I need a strategy to redirect the webservers to the failover database instance IP when the primary database instance fails.
I was hoping I could use an Elastic IP in my connection strings. But, the webservers are not able to access/ping the Elastic IP. I have several brute force ideas to solve the problem. However, I am trying to find the most elegant solution possible.
I am using all .Net and SQL Server. My connection strings are encrypted.
Does anybody have a strategy for failing over a database instance in EC2 using some form of automation or DNS configuration?
Please let me know.
http://alestic.com/2009/06/ec2-elastic-ip-internal
tells you how to use the Elastic IP public DNS.
Haven't used EC2 but surely you need to either:
(a) put your front-end into some custom maintenance mode, that you define, while you switch the IP over; and have the front-end perform required steps to manage potential data integrity and data loss issues related to the previous server going down and the new server coming up when it enters and leaves your custom maintenance mode
OR, for a zero down-time system:
(b) design the system at the object/relational and transaction levels from the ground up to support zero-down-time fail-over. It's not something you can bolt on quicjkly to just any application.
(c) use some database support for automatic failover. I am unaware whether SQL Server support for failover suitable for your application exists or is appropriate here. I suggest adding a "sql-server" tag to the question to start a search for the right audience.
If Elastic IPs don't work (which sounds odd to say the least - shouldn't you talk to EC2 about that), you mayhave to be able to instruct your front-end which new database IP to use at the same time as telling it to go from maintenance mode to normal mode.
If you're willing to shell out a bit of extra money, take a look at Rightscale's tools; they've built custom server images and supporting tools that handle database failover (among many other things). This link explains how to do it with MySQL, so will hopefully show you some principles even though it doesn't use SQL Server.
I always thought there was this possibility in the connnection string
This is taken (but not yet tested) from How to add Failover Partner to a connection string in VB.NET :
If you connect with ADO.NET or the SQL
Native Client to a database that is
being mirrored, your application can
take advantage of the drivers ability
to automatically redirect connections
when a database mirroring failover
occurs. You must specify the initial
principal server and database in the
connection string and the failover
partner server.
Data Source=myServerAddress;Failover Partner=myMirrorServerAddress;
Initial Catalog=myDataBase;Integrated Security=True;
There is ofcourse many other ways to
write the connection string using
database mirroring, this is just one
example pointing out the failover
functionality. You can combine this
with the other connection strings
options available.
To broaden gareth's answer, cloud management softwares usually solve this type of problems. RightScale is one of them, but you can try enStratus or Scalr (disclaimer: I work at Scalr). These tools provide failover solutions like:
Backups: you can schedule automated snapshots of the EBS volume containing the data
Fault-tolerant database: in the event of failure, a slave is promoted master and mounted storage will be switched if the failed master and new master are in the same AZ, or a snapshot taken of the volume
If you want to build your own solution, you could replicate the process detailed below that we use at Scalr:
Is there a slave in the same AZ? If so, promote it, switch EBS
volumes (which are limited to a single AZ), switch any ElasticIP you
might have, reconfigure replication of the remaining slaves.
If not, is there a slave fully replicated in another AZ? If so, promote it,
then do the above.
If there are no slave in same AZ, and no slave fully
replicated in another AZ, then create a snapshot from master's
volume, and use this snapshot to create a new volume in an AZ where a
slave is running. Then do the above.