SSH without password only works one time

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I want to configure SSH to use it without the need of writing the password. I am using Ubuntu 18.04 LTS on Windows 10. I need it to run Hadoop 3.1.1 (https://hadoop.apache.org/docs/r3.1.1/hadoop-project-dist/hadoop-common/SingleCluster.html#Standalone_Operation) using the pseudo-distributed mode.

I have tried a lot of different solutions but without any result. I obtained that the first time that I used the command ssh localhost I do not need to write the passphrase but when I write again I have to write the passphrase.

I explain the different steps that I have used:

I have created a key using ssh-keygen -t rsa

I add the public key to the authorized_keys files: cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys

I add the key executing: exec ssh-agent bash and ssh-add id_rsa (Years ago, in this point sometimes I had different problems and I used different solutions: https://superuser.com/questions/1147145/what-are-the-differences-between-the-those-ways-of-using-the-ssh-agent)

I execute: ssh localhost

At this point all is right, but, when I execute again ssh localhost, then, I have to write the passphrase. These steps worked fine in the Ubuntu of AWS 3 years ago.

I have tried in the point 3 this other method: https://www.ssh.com/ssh/copy-id

All the possible solutions that I found said the same that I have tried in point 3, or I think that. I have tried to change permissions of authorized_keys and .ssh as I found in other solutions too but without success.

asked 3 hours ago

CGG

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up vote
1
down vote

favorite

I explain the different steps that I have used:

I have created a key using ssh-keygen -t rsa

I add the public key to the authorized_keys files: cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys

I add the key executing: exec ssh-agent bash and ssh-add id_rsa (Years ago, in this point sometimes I had different problems and I used different solutions: https://superuser.com/questions/1147145/what-are-the-differences-between-the-those-ways-of-using-the-ssh-agent)

I execute: ssh localhost

At this point all is right, but, when I execute again ssh localhost, then, I have to write the passphrase. These steps worked fine in the Ubuntu of AWS 3 years ago.

I have tried in the point 3 this other method: https://www.ssh.com/ssh/copy-id

asked 3 hours ago

CGG

1063

New contributor

add a commentÂ |Â

up vote
1
down vote

favorite

I explain the different steps that I have used:

I have created a key using ssh-keygen -t rsa

I add the public key to the authorized_keys files: cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys

I add the key executing: exec ssh-agent bash and ssh-add id_rsa (Years ago, in this point sometimes I had different problems and I used different solutions: https://superuser.com/questions/1147145/what-are-the-differences-between-the-those-ways-of-using-the-ssh-agent)

I execute: ssh localhost

At this point all is right, but, when I execute again ssh localhost, then, I have to write the passphrase. These steps worked fine in the Ubuntu of AWS 3 years ago.

I have tried in the point 3 this other method: https://www.ssh.com/ssh/copy-id

asked 3 hours ago

CGG

1063

New contributor

I explain the different steps that I have used:

I have created a key using ssh-keygen -t rsa

I add the public key to the authorized_keys files: cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys

I add the key executing: exec ssh-agent bash and ssh-add id_rsa (Years ago, in this point sometimes I had different problems and I used different solutions: https://superuser.com/questions/1147145/what-are-the-differences-between-the-those-ways-of-using-the-ssh-agent)

I execute: ssh localhost

At this point all is right, but, when I execute again ssh localhost, then, I have to write the passphrase. These steps worked fine in the Ubuntu of AWS 3 years ago.

I have tried in the point 3 this other method: https://www.ssh.com/ssh/copy-id

18.04 ssh configuration openssh hadoop

asked 3 hours ago

CGG

1063

New contributor

asked 3 hours ago

CGG

1063

New contributor

asked 3 hours ago

CGG

1063

New contributor

asked 3 hours ago

CGG

1063

asked 3 hours ago

CGG

1063

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CGG is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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up vote
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You should take a look at this answer which describes configuring ssh for your user (editing ~/.ssh/config) and other details.

The steps are:

Generate your ssh key.

Add the Host to your ~/.ssh/config file.

Add your Public (.pub) key to the remote user's ~/.ssh/authorized_keys
- This is most easily done with ssh-copy-id command.
- ssh is very particular about the permissions of ~/.ssh/ and the files found within. ssh-copy-id handles everything for you.

Try connecting to the Host:
- ssh host
- ssh host -vvv # Verbose output for troubleshooting

Are you trying to use ssh-agent because your keys are protected by a password? I would recommend working on manually connecting without ssh-agent and getting that working. After you have your key working, you can work on solving any of the ssh-agent-specific issues.

To troubleshoot, be sure to use ssh in a verbose mode, and also monitor (tail -f) the remote server's /var/log/auth.log file. On newer systems, you may have to use journalctl (journalctl -u sshd | tail -f).

Once you've gotten the key working in general, you can look into ssh-agent documentation, such as this set of setup instructions. Typically the steps are as follows:

Generate your keys (as you have already done).

Install the keys (as you have already done).

Start ssh-agent
- eval ssh-agent
- Only once, not each connection or anything.
- You can have this happen automatically, depending on when and for which user.

Add your key to ssh-agent:
- ssh-add ~/.ssh/private_key

Be sure to look into other ssh-agent configuration options, such as the duration your keys will remain unlocked.

Boiling it down a bit, your problem is most likely one of these:

You say you added ssh-agent starting, and the addition of your id_rsa key (in the past), but now that you've generated a new key, that key will also need to be ssh-add'd.
- Check that ssh-agent is actually running on your system if you have problems after adding the key.
- ps aux | ssh-agent

You're adding the key to your local file, not the remote user's file.
- Think of it like you're adding a password, so you need to add the password on the system which should accept it.
- Your remote host is localhost, but this assumes you'll want to be able to work on remote hosts in the future.

You say it works a single time? Does it work twice if you try two times in a shorter timeframe, say one minute? I am trying to understand if your ssh-agent is just set up to lock your key in a shorter timeframe than you've tested.

When appending to the ~/.ssh/authorized_keys file (>>), you initially created the file, and this would be with incorrect permissions.
- Do not do the following without securing access, and making backups to any remote files.
- If your 'remote host' is localhost, it very likely has files you want to keep, such as your keys, and should be backed up before removal.
- Delete the entire remote ~/.ssh/ directory and use ssh-copy-id to properly key your user on the remote host.
- This would show up on the remote host's auth.log and specify that the file permissions are incorrect.
- If you continue to experience issues after using ssh-copy-id to create the directory and files, post the permissions of ~/.ssh and your generated key files.

edited 2 hours ago

answered 3 hours ago

earthmeLon

6,0331648

THX: 2 problems. If I use 'eval ssh-agent' because when I use ssh-add id_rsa the system return me 'Could not open a connection to your authentication agent.' Then, I have to use 'exec ssh-agent bash'.
â€“Â CGG
1 hour ago

The other problem: I said it works in a single time because I execute 'ssh localhost' and then I do not require to introduce the passphrase. If I execute again 'ssh localhost', then, I have to insert the passphrase.
â€“Â CGG
1 hour ago

add a commentÂ |Â

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1 Answer
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up vote
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You should take a look at this answer which describes configuring ssh for your user (editing ~/.ssh/config) and other details.

The steps are:

Generate your ssh key.

Add the Host to your ~/.ssh/config file.

Add your Public (.pub) key to the remote user's ~/.ssh/authorized_keys
- This is most easily done with ssh-copy-id command.
- ssh is very particular about the permissions of ~/.ssh/ and the files found within. ssh-copy-id handles everything for you.

Try connecting to the Host:
- ssh host
- ssh host -vvv # Verbose output for troubleshooting

Once you've gotten the key working in general, you can look into ssh-agent documentation, such as this set of setup instructions. Typically the steps are as follows:

Generate your keys (as you have already done).

Install the keys (as you have already done).

Start ssh-agent
- eval ssh-agent
- Only once, not each connection or anything.
- You can have this happen automatically, depending on when and for which user.

Add your key to ssh-agent:
- ssh-add ~/.ssh/private_key

Be sure to look into other ssh-agent configuration options, such as the duration your keys will remain unlocked.

Boiling it down a bit, your problem is most likely one of these:

You say you added ssh-agent starting, and the addition of your id_rsa key (in the past), but now that you've generated a new key, that key will also need to be ssh-add'd.
- Check that ssh-agent is actually running on your system if you have problems after adding the key.
- ps aux | ssh-agent

You're adding the key to your local file, not the remote user's file.
- Think of it like you're adding a password, so you need to add the password on the system which should accept it.
- Your remote host is localhost, but this assumes you'll want to be able to work on remote hosts in the future.

You say it works a single time? Does it work twice if you try two times in a shorter timeframe, say one minute? I am trying to understand if your ssh-agent is just set up to lock your key in a shorter timeframe than you've tested.

When appending to the ~/.ssh/authorized_keys file (>>), you initially created the file, and this would be with incorrect permissions.
- Do not do the following without securing access, and making backups to any remote files.
- If your 'remote host' is localhost, it very likely has files you want to keep, such as your keys, and should be backed up before removal.
- Delete the entire remote ~/.ssh/ directory and use ssh-copy-id to properly key your user on the remote host.
- This would show up on the remote host's auth.log and specify that the file permissions are incorrect.
- If you continue to experience issues after using ssh-copy-id to create the directory and files, post the permissions of ~/.ssh and your generated key files.

edited 2 hours ago

answered 3 hours ago

earthmeLon

6,0331648

THX: 2 problems. If I use 'eval ssh-agent' because when I use ssh-add id_rsa the system return me 'Could not open a connection to your authentication agent.' Then, I have to use 'exec ssh-agent bash'.
â€“Â CGG
1 hour ago

The other problem: I said it works in a single time because I execute 'ssh localhost' and then I do not require to introduce the passphrase. If I execute again 'ssh localhost', then, I have to insert the passphrase.
â€“Â CGG
1 hour ago

add a commentÂ |Â

up vote
3
down vote

You should take a look at this answer which describes configuring ssh for your user (editing ~/.ssh/config) and other details.

The steps are:

Generate your ssh key.

Add the Host to your ~/.ssh/config file.

Add your Public (.pub) key to the remote user's ~/.ssh/authorized_keys
- This is most easily done with ssh-copy-id command.
- ssh is very particular about the permissions of ~/.ssh/ and the files found within. ssh-copy-id handles everything for you.

Try connecting to the Host:
- ssh host
- ssh host -vvv # Verbose output for troubleshooting

Once you've gotten the key working in general, you can look into ssh-agent documentation, such as this set of setup instructions. Typically the steps are as follows:

Generate your keys (as you have already done).

Install the keys (as you have already done).

Start ssh-agent
- eval ssh-agent
- Only once, not each connection or anything.
- You can have this happen automatically, depending on when and for which user.

Add your key to ssh-agent:
- ssh-add ~/.ssh/private_key

Be sure to look into other ssh-agent configuration options, such as the duration your keys will remain unlocked.

Boiling it down a bit, your problem is most likely one of these:

You say you added ssh-agent starting, and the addition of your id_rsa key (in the past), but now that you've generated a new key, that key will also need to be ssh-add'd.
- Check that ssh-agent is actually running on your system if you have problems after adding the key.
- ps aux | ssh-agent

You're adding the key to your local file, not the remote user's file.
- Think of it like you're adding a password, so you need to add the password on the system which should accept it.
- Your remote host is localhost, but this assumes you'll want to be able to work on remote hosts in the future.

You say it works a single time? Does it work twice if you try two times in a shorter timeframe, say one minute? I am trying to understand if your ssh-agent is just set up to lock your key in a shorter timeframe than you've tested.

When appending to the ~/.ssh/authorized_keys file (>>), you initially created the file, and this would be with incorrect permissions.
- Do not do the following without securing access, and making backups to any remote files.
- If your 'remote host' is localhost, it very likely has files you want to keep, such as your keys, and should be backed up before removal.
- Delete the entire remote ~/.ssh/ directory and use ssh-copy-id to properly key your user on the remote host.
- This would show up on the remote host's auth.log and specify that the file permissions are incorrect.
- If you continue to experience issues after using ssh-copy-id to create the directory and files, post the permissions of ~/.ssh and your generated key files.

edited 2 hours ago

answered 3 hours ago

earthmeLon

6,0331648

THX: 2 problems. If I use 'eval ssh-agent' because when I use ssh-add id_rsa the system return me 'Could not open a connection to your authentication agent.' Then, I have to use 'exec ssh-agent bash'.
â€“Â CGG
1 hour ago

The other problem: I said it works in a single time because I execute 'ssh localhost' and then I do not require to introduce the passphrase. If I execute again 'ssh localhost', then, I have to insert the passphrase.
â€“Â CGG
1 hour ago

add a commentÂ |Â

up vote
3
down vote

You should take a look at this answer which describes configuring ssh for your user (editing ~/.ssh/config) and other details.

The steps are:

Generate your ssh key.

Add the Host to your ~/.ssh/config file.

Add your Public (.pub) key to the remote user's ~/.ssh/authorized_keys
- This is most easily done with ssh-copy-id command.
- ssh is very particular about the permissions of ~/.ssh/ and the files found within. ssh-copy-id handles everything for you.

Try connecting to the Host:
- ssh host
- ssh host -vvv # Verbose output for troubleshooting

Once you've gotten the key working in general, you can look into ssh-agent documentation, such as this set of setup instructions. Typically the steps are as follows:

Generate your keys (as you have already done).

Install the keys (as you have already done).

Start ssh-agent
- eval ssh-agent
- Only once, not each connection or anything.
- You can have this happen automatically, depending on when and for which user.

Add your key to ssh-agent:
- ssh-add ~/.ssh/private_key

Be sure to look into other ssh-agent configuration options, such as the duration your keys will remain unlocked.

Boiling it down a bit, your problem is most likely one of these:

You say you added ssh-agent starting, and the addition of your id_rsa key (in the past), but now that you've generated a new key, that key will also need to be ssh-add'd.
- Check that ssh-agent is actually running on your system if you have problems after adding the key.
- ps aux | ssh-agent

You're adding the key to your local file, not the remote user's file.
- Think of it like you're adding a password, so you need to add the password on the system which should accept it.
- Your remote host is localhost, but this assumes you'll want to be able to work on remote hosts in the future.

You say it works a single time? Does it work twice if you try two times in a shorter timeframe, say one minute? I am trying to understand if your ssh-agent is just set up to lock your key in a shorter timeframe than you've tested.

When appending to the ~/.ssh/authorized_keys file (>>), you initially created the file, and this would be with incorrect permissions.
- Do not do the following without securing access, and making backups to any remote files.
- If your 'remote host' is localhost, it very likely has files you want to keep, such as your keys, and should be backed up before removal.
- Delete the entire remote ~/.ssh/ directory and use ssh-copy-id to properly key your user on the remote host.
- This would show up on the remote host's auth.log and specify that the file permissions are incorrect.
- If you continue to experience issues after using ssh-copy-id to create the directory and files, post the permissions of ~/.ssh and your generated key files.

edited 2 hours ago

answered 3 hours ago

earthmeLon

6,0331648

You should take a look at this answer which describes configuring ssh for your user (editing ~/.ssh/config) and other details.

The steps are:

Generate your ssh key.

Add the Host to your ~/.ssh/config file.

Add your Public (.pub) key to the remote user's ~/.ssh/authorized_keys
- This is most easily done with ssh-copy-id command.
- ssh is very particular about the permissions of ~/.ssh/ and the files found within. ssh-copy-id handles everything for you.

Try connecting to the Host:
- ssh host
- ssh host -vvv # Verbose output for troubleshooting

Once you've gotten the key working in general, you can look into ssh-agent documentation, such as this set of setup instructions. Typically the steps are as follows:

Generate your keys (as you have already done).

Install the keys (as you have already done).

Start ssh-agent
- eval ssh-agent
- Only once, not each connection or anything.
- You can have this happen automatically, depending on when and for which user.

Add your key to ssh-agent:
- ssh-add ~/.ssh/private_key

Be sure to look into other ssh-agent configuration options, such as the duration your keys will remain unlocked.

Boiling it down a bit, your problem is most likely one of these:

You say you added ssh-agent starting, and the addition of your id_rsa key (in the past), but now that you've generated a new key, that key will also need to be ssh-add'd.
- Check that ssh-agent is actually running on your system if you have problems after adding the key.
- ps aux | ssh-agent

You're adding the key to your local file, not the remote user's file.
- Think of it like you're adding a password, so you need to add the password on the system which should accept it.
- Your remote host is localhost, but this assumes you'll want to be able to work on remote hosts in the future.

You say it works a single time? Does it work twice if you try two times in a shorter timeframe, say one minute? I am trying to understand if your ssh-agent is just set up to lock your key in a shorter timeframe than you've tested.

When appending to the ~/.ssh/authorized_keys file (>>), you initially created the file, and this would be with incorrect permissions.
- Do not do the following without securing access, and making backups to any remote files.
- If your 'remote host' is localhost, it very likely has files you want to keep, such as your keys, and should be backed up before removal.
- Delete the entire remote ~/.ssh/ directory and use ssh-copy-id to properly key your user on the remote host.
- This would show up on the remote host's auth.log and specify that the file permissions are incorrect.
- If you continue to experience issues after using ssh-copy-id to create the directory and files, post the permissions of ~/.ssh and your generated key files.

edited 2 hours ago

answered 3 hours ago

earthmeLon

6,0331648

edited 2 hours ago

answered 3 hours ago

earthmeLon

6,0331648

answered 3 hours ago

earthmeLon

6,0331648

answered 3 hours ago

earthmeLon

6,0331648

THX: 2 problems. If I use 'eval ssh-agent' because when I use ssh-add id_rsa the system return me 'Could not open a connection to your authentication agent.' Then, I have to use 'exec ssh-agent bash'.
â€“Â CGG
1 hour ago

The other problem: I said it works in a single time because I execute 'ssh localhost' and then I do not require to introduce the passphrase. If I execute again 'ssh localhost', then, I have to insert the passphrase.
â€“Â CGG
1 hour ago

add a commentÂ |Â

THX: 2 problems. If I use 'eval ssh-agent' because when I use ssh-add id_rsa the system return me 'Could not open a connection to your authentication agent.' Then, I have to use 'exec ssh-agent bash'.
â€“Â CGG
1 hour ago

The other problem: I said it works in a single time because I execute 'ssh localhost' and then I do not require to introduce the passphrase. If I execute again 'ssh localhost', then, I have to insert the passphrase.
â€“Â CGG
1 hour ago

THX: 2 problems. If I use 'eval ssh-agent' because when I use ssh-add id_rsa the system return me 'Could not open a connection to your authentication agent.' Then, I have to use 'exec ssh-agent bash'.
â€“Â CGG
1 hour ago

The other problem: I said it works in a single time because I execute 'ssh localhost' and then I do not require to introduce the passphrase. If I execute again 'ssh localhost', then, I have to insert the passphrase.
â€“Â CGG
1 hour ago

add a commentÂ |Â

CGG is a new contributor. Be nice, and check out our Code of Conduct.

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