amazon-ssm-agent: aws ssm start-session end with Cannot perform start session: EOF

I try to instanciate a vanilla aws ssm start-session on a Github actions Jobs (without SSH).

The session is well instanciated (i can see it on the AWS Session Manager dashboard) but always finish with a Cannot perform start session: EOF

FYI I can instanciated a sesion outside of GH actions (.e.g. on my laptop) with the same account / role / policy / instances (ami-0ea4a063871686f37).

Here’s my job YAML :

name: CI

# Controls when the action will run. 
on:
  # Triggers the workflow on push or pull request events but only for the main branch
  push:
    branches: [ main ]
  pull_request:
    branches: [ main ]

# A workflow run is made up of one or more jobs that can run sequentially or in parallel
jobs:
  # This workflow contains a single job called "build"
  build:
    # The type of runner that the job will run on
    runs-on: ubuntu-latest

    # Steps represent a sequence of tasks that will be executed as part of the job
    steps:
      - name: Configure AWS credentials from Test account
        uses: aws-actions/configure-aws-credentials@v1
        with:
          aws-access-key-id: ${{ secrets.AWS_ACCESS_KEY_ID }}
          aws-secret-access-key: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
          aws-region: ${{ secrets.AWS_REGION }}
                   
      - name: Initialize a Session Manager session
        shell : sh
        run: aws ssm start-session --target ${{ secrets.TARGET_INSTANCE }}

The results :

Run aws ssm start-session --target ***
  aws ssm start-session --target ***
  shell: /bin/sh -e {0}
  env:
    AWS_DEFAULT_REGION: ***
    AWS_REGION: ***
    AWS_ACCESS_KEY_ID: ***
    AWS_SECRET_ACCESS_KEY: ***

Starting session with SessionId: gh-ssm-0d50831b64f0xxxxx
$ Cannot perform start session: EOF

Here are the CLI tools packaged with Ubuntu-latest virtual env (20.04.2 LTS) :

AWS CLI 2.1.24
AWS CLI Session manager plugin 1.2.54.0

About this issue

Original URL
State: open
Created 3 years ago
Reactions: 14
Comments: 19 (2 by maintainers)

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Most upvoted comments

I had similar issue with “aws ecs execute-command …” and it seems it’s related to tty being not available when running in ci

I fixed it with “unbuffer aws ecs execute-command …” to run it with tty available

+19

olfway on Apr 11, 2021

Yes, I am invoking it from a terminal. I haven’t changed anything about the instances I’m connecting to, they’re launched from an AMI I baked weeks ago. It’s working today, without changing anything in my local environment (same version of session-manager-plugin, same AMI/instances)

When a shell session is started, session manager plugin also fetches terminal size on client machine and sends it to pseudo terminal on target server.

ah, I think I get it. When I try the same command from a terminal with an enormous scrollback, it fails with Cannot perform start session: EOF. Using a new terminal session clears the scrollback, and aws ssm start-session works as expected.

dgholz on May 24, 2021

More on unbuffer & expect https://stackoverflow.com/questions/66066753/aws-start-session-end-with-cannot-perform-start-session-eof

Side note, you can run single commands like so

unbuffer aws ssm start-session \
         --document-name 'AWS-StartNonInteractiveCommand' \
         --parameters '{"command": ["sudo sh -c \"systemctl status boot_scripts && ( journalctl -u boot_scripts | cat )\""]}' \
         --target "$instanceid"

RichardTMiles on Sep 5, 2022

I had similar issue with “aws ecs execute-command …” and it seems it’s related to tty being not available when running in ci

I fixed it with “unbuffer aws ecs execute-command …” to run it with tty available

@olfway You saved my day! I had the exact same issue and sudo apt-get install expect; aws ecs execute-command .... worked like a charm! Thanks.

zengben-gainfully on Jun 6, 2021

Session manager plugin has been designed to be invoked from a terminal for shell scenarios so it can interpret control sequences returned by pseudo terminal and display appropriately. When a shell session is started, session manager plugin also fetches terminal size on client machine and sends it to pseudo terminal on target server. We suspect one of these actions might be failing for you. Please let us know if you are invoking session manager plugin from a terminal and still seeing error of Cannot perform start session: EOF.

nitikaaws on May 18, 2021

@alxsbn Can you explain more what you meant by “ssm send-command with remote script execution”? We’re running into the same issue with

aws ecs execute-command

I don’t know if this makes a difference, but we’re using ECS with Fargate, not EC2.

emmahsax on Apr 29, 2021

Thank you. The command that I tried to execute is what OP tried: aws ssm start-session --target i-xyz .

I added unbuffer to the beginning, same error: unbuffer aws ssm start-session --target i-xyz . My question was, why using unbuffer would make it work?

aries1980 on Nov 10, 2023

maybe this command can help

name: Install AWS CLI run: | sudo apt-get update sudo apt-get install -y awscli aws --version
name: Configure AWS credentials uses: aws-actions/configure-aws-credentials@v1 with: aws-access-key-id: ${{ secrets.AWS_ACCESS_KEY_ID }} aws-secret-access-key: ${{ secrets.AWS_SECRET_ACCESS_KEY }} aws-region: ${{ secrets.AWS_DEFAULT_REGION }}
name: Install Session Manager Plugin run: | curl “https://s3.amazonaws.com/session-manager-downloads/plugin/latest/ubuntu_64bit/session-manager-plugin.deb” -o “session-manager-plugin.deb” sudo dpkg -i session-manager-plugin.deb sudo apt-get update sudo apt-get install -y session-manager-plugin sudo apt-get install -y expect session-manager-plugin --version
name: Create Start SSH Session shell : sh run: | aws ssm start-session
–target ${{ secrets.INSTANCE_ID }}
–document-name AWS-StartSSHSession

wissnusetiawan on Apr 24, 2023

@emmahsax Our first reflex was to run a ssh command, then the others commands we need (for us it was linked to CD, so rsync a repo then restart a pm2 service). Since we have this tty problem we just write a shell script with our commands an fire him with ssm send-command

alxsbn on Apr 29, 2021

amazon-ssm-agent: aws ssm start-session end with **Cannot perform start session: EOF**

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amazon-ssm-agent: aws ssm start-session end with Cannot perform start session: EOF