I want to deploy my infrastructure in different AWS environments (dev, prod, qa).
That deployment creates a few EC2 instances from a custom AMI. When deployed, instances are in the "running" state. I understand this seems to be related to some constraint in the EC2 API. However, I don't necessarily want my instances started, depending on context. Sometimes, I just want the instances to be created, and they will be started later on. I guess this is a quite common scenario.
Reading the few related issues/requests on Hashicorp's github, makes me think so:
Terraform aws instance state change
Stop instances
aws_instance should allow to specify the instance state
There must be some TerraForm based solution which doesn't require to rely on AWS CLI / CDK or lambda, right? Something in the TerraForm script that, for example, would stop the instance right after its creation.
My google foo didn't help me much here. Any help / suggestion for dealing with that scenario is welcome.
Provisioning a new instance automatically puts it in a 'started' state.
As Marcin suggested, you can use user data scripts, here's some psuedo user data script. For you to figure out the actual implementation ;)
#!/bin/bash
get instance id, pass it to the subsequent line
aws ec2 stop-instances --instance-ids i-1234567890abcdef0
You can read about running scripts as part of the bootstrapping here: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/user-data.html
Basically its all up to your use case. We don't do this generally. Still, if you want to provision your EC2 instances and need to put them in stopped state, as bschaatsbergen suggested, you can use the user_data in Terraform. Make sure to attach the role with relevant permission.
#!/bin/bash
INSTANCE_ID=`curl -s http://169.254.169.254/latest/meta-data/instance-id/`
REGION=`curl -s http://169.254.169.254/latest/meta-data/placement/availability-zone | sed 's/.$//'`
aws ec2 stop-instances --instance-ids $INSTANCE_ID --region $REGION
As already stated by others, you cannot just "create" instances, they will be in "started" state.
Rather I would ask what is the exact use case here :
Sometimes, I just want the instances to be created, and they will be started later on.
Why you have to create instances now and use them later? Can't they be created exactly when they are required? Any specific requirement to keep them initialized before they are used? Or the instances take time to start?
Related
Hoping I'll catch a break as a complete ECS NOOB =)
So far I think I've managed to build out a good start, using ECS-CLI to create a cluster for two docker containers that go together and should run on the same instance (x2). However, at the time of either my ecs-cli up or my ecs-cli compose, I need to get the command to build the task in such a way that it can access a set of environment variables stored in AWS Parameter Store. I don't see any options to do that with ecs-cli, for neither 'up' nor 'compose'.
What am I missing? Help! I'm not sure yet what other info to provide, or I'd post all that I can, so please let me know what other data/background you need if you think you have an answer.
All comments very much appreciated of course!
See the secrets section in the ecs-cli documentation here. You would configure ECS to pull those secrets from SSM Parameter Store and inject them as environment variables into your container using that method.
I have an ec2 micro instance. I can start it from the console, ssh into it (using a .pem file) and visit the website it hosts.
Using the old ec2 CLI, I can start the instance and perform other actions including ssh and website access.
I am having trouble with the new ec2 CLI. When I do "aws ec2 start-instances --instance-ids i-xxx" I get the message "A client error (InvalidInstanceID.NotFound) occurred when calling the StartInstances operation: The instance ID 'i-xxx' does not exist".
Clearly the instance exists, so I don't what the message is really indicating.
Here is some of my thinking:
One difference between the old and new CLI is that the the later used .pem files whereas the new interface uses access key pairs. The instance has an access key pair associated with is, but have tried all the credentials I can find, and none of them change anything).
I tried created an IAM user and a new access key pair for it. The behavior in all cases is unchanged (start from console or old CLI, web access, ssh) but not using the new CLI.
I realize that there is a means for updating the access key pairs by detaching the volume (as described here), but the process looks a little scary to me.
I realize that I can clone another instance from the image, but the image is a little out of date, and I don't want to lose my changes.
Can anyone suggest what the message really means and what I can do to get around the problem?
The problem had to do with credentials. I had the correct environment
variables (AWS_ACCESS_KEY and AWS_SECRET_KEY) set. But they didn't match what was in my .aws/credentials file. That is, despite what it says here, the new CLI worked only when I had the environment variables and
the credentials file correct and in sync.
Configure your aws cli with "aws configure" in new cli instance with region in which your ec2 instance reside. and then try to give the same command. The instance should start.
I'd like to get EC2 instances metadata with Ansible and do something with those instances based on the metadata. However, ec2_facts wants to SSH into instances in order to get the metadata.
I believe it should be possible to obtain the instances metadata without SSH connections.
Could you help me with that please?
Thank you.
There is information you can retrieve about instances using the aws API but ec_facts does not use it. What that Ansible module does specifically is fetch metadata via http://169.254.169.254/latest/meta-data/ which can only be done from the instance itself.
Some more information about what instance data you wish to fetch would be helpful to know. At this time there is no aws cloud module in core that will retrieve general information about an instance but Ansible makes it easy to write one.
Here is an example of a module that returns information about instances that match a set of tags - https://github.com/edx/configuration/blob/master/playbooks/library/ec2_lookup
I'm creating an init.d script that will run a couple of tasks when the instance starts up.
it will create a new volume with our code repository and mount it if it doesn't exist already.
it will tag the instance
The tasks above being complete will be crucial for our site (i.e. without the code repository mounted the site won't work). How can I make sure that the server doesn't end up being publicly visible? Should I start my init.d script with de-registering the instance from the ELB (I'm not even sure if it will be registered at that point), and then register it again when all the tasks finished successfully?
What is the best practice?
Thanks!
You should have a health check on your ELB. So your server shouldn't get in unless it reports as happy. And it shouldn't report happy if the boot script errors out.
(Also, you should look into using cloud-init. That way you can change the boot script without making a new AMI.)
I suggest you use CloudFormation instead. You can bring up a full stack of your system by representing it in a JSON format template.
For example, you can create an autoscale group that has an instances with unique tags and the instances have another volume attached (which presumably has your code)
Here's a sample JSON template attaching an EBS volume to an instance:
https://s3.amazonaws.com/cloudformation-templates-us-east-1/EC2WithEBSSample.template
And here many other JSON templates that you can use for your guidance and deploy your specific Stack and Application.
http://aws.amazon.com/cloudformation/aws-cloudformation-templates/
Of course you can accomplish the same using init.d script or using the rc.local file in your instance but I believe CloudFormation is a cleaner solution from the outside (not inside your instance)
You can also write your own script that brings up your stack from the outside by why reinvent the wheel.
Hope this helps.
I would like to create a new instance based on my stored AMI.
I achieve this by the following code:
RunInstancesRequest rir = new RunInstancesRequest(imageId,1, 1);
// Code for configuring the settings of the new instance
...
RunInstancesResult runResult = ec2.runInstances(rir);
However, I cannot find a wait to "block"/wait until the instance is up and running apart from Thread.currentThread().sleep(xxxx) command.
On the other hand, StartInstancesResult and TerminateInstancesResult gives you a way to have access on the state of the instances and be able to monitor any changes. But, what about the state of a completely new instance?
boto3 has:
instance.wait_until_running()
From the boto3 docs:
Waits until this Instance is running. This method calls EC2.Waiter.instance_running.wait() which polls EC2.Client.describe_instances() every 15 seconds until a successful state is reached. An error is returned after 40 failed checks.
From the AWS CLI changelog for v1.6.0:
Add a wait subcommand that allows for a command to block until an AWS
resource reaches a given state (issue 992, issue 985)
I don't see this mentioned in the documentation, but the following worked for me:
aws ec2 start-instances --instance-ids "i-XXXXXXXX"
aws ec2 wait instance-running --instance-ids "i-XXXXXXXX"
The wait instance-running line did not finish until the EC2 instance was running.
I don't use Python/boto/botocore but assume it has something similar. Check out waiter.py on Github.
Waiting for the EC2 instance to get ready is a common pattern. In the Python library boto you also solve this with sleep calls:
reservation = conn.run_instances([Instance configuration here])
instance = reservation.instances[0]
while instance.state != 'running':
print '...instance is %s' % instance.state
time.sleep(10)
instance.update()
With this mechanism you will be able to poll when your new instance will come up.
Depending on what you are trying to do (and how many servers you plan on starting), instead of polling for the instance start events, you could install on the AMI a simple program/script that runs once when the instance starts and sends out a notification to that effect, i.e. to an AWS SNS Topic.
The process that needs to know about new servers starting could then subscribe to this SNS topic, and would receive a push notifications each time a server starts.
Solves the same problem from a different angle; your mileage may vary.
Go use Boto3's wait_until_running method:
http://boto3.readthedocs.io/en/latest/reference/services/ec2.html#EC2.Instance.wait_until_running
You can use boto3 waiters,
https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/ec2.html#waiters
for this ex: https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/ec2.html#EC2.Waiter.InstanceRunning
Or in Java https://docs.aws.amazon.com/AWSJavaSDK/latest/javadoc/
I am sure there are waiters implemented in all the AWS sdks.