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| other:ssh [2023/03/15 11:47] – [Configuration files] Improved jypeter | other:ssh [2023/03/23 11:02] – [What are ssh keys and why use them?] Improved jypeter |
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| * [[https://documentations.ipsl.fr/MESO_User/Quick_start.html|More details]] | * [[https://documentations.ipsl.fr/MESO_User/Quick_start.html|More details]] |
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| === TGCC servers === | === TGCC (super)computers === |
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| If you want to connect to the the **TGCC servers**: | If you want to use the [[https://www-hpc.cea.fr/tgcc-public/en/html/tgcc-public.html|TGCC computers]] (e.g. ''irene''): |
| * Connecting to ''irene'': | |
| * Note: you have to go trough ''ssh1'', even if you are on the LSCE network! | |
| * ''ssh -A -X my_LSCE_login@ssh1.lsce.ipsl.fr -t ssh -A -X my_TGCC_login@irene-ccrt.ccc.cea.fr'' | |
| * The [[https://intranet.lsce.ipsl.fr/informatique/en/tgcc.php|TGCC connection details]] may vary, depending on your login type | |
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| === IDRIS servers === | * Note: you have to go //trough// the ''ssh1'' LSCE gateway to access the TGCC, even if you are on the LSCE wired network! |
| | * ''ssh -A -X my_LSCE_login@ssh1.lsce.ipsl.fr -t ssh -A -X my_TGCC_login@some_tgcc_login_node'' |
| | * Once you are on a TGCC login node (e.g. ''irene''), you can get lots of information by typing ''<node>.info'' (e.g. ''irene.info'') |
| | * [[https://intranet.lsce.ipsl.fr/informatique/en/tgcc.php|more TGCC connection details]] |
| | |
| | === IDRIS (super)computers === |
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| FIXME | FIXME |
| ''ssh'' will store all its **configuration files** in a ''.ssh'' sub-directory of your //home// directory. The configuration files are in a //text// format. | ''ssh'' will store all its **configuration files** in a ''.ssh'' sub-directory of your //home// directory. The configuration files are in a //text// format. |
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| * Linux: ''~/.ssh/'' directory | * **Linux**: ''~/.ssh/'' directory |
| * Windows: ''C:\Users\your_windows_login\.ssh'' directory | * **Windows**: ''C:\Users\your_windows_login\.ssh'' directory |
| * Mac: ''/Users/your_mac_login/.ssh'' directory (should be the same path as ''~/.ssh/'') | * **Mac**: ''/Users/your_mac_login/.ssh'' directory (should be the same path as ''~/.ssh/'') |
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| You will find (some of) the following text files: | You will find (some of) the following text files: |
| ==== What are ssh keys and why use them? ==== | ==== What are ssh keys and why use them? ==== |
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| //ssh keys// are a combination of two specific (and unique) **text files**, **the private key** file and **the public key** file, linked by a special kind of password called **the passphrase**, that can be used instead of a standard password to connect securely from one server to another server | //ssh keys// are a combination of two specific (and unique) **text files**, **the //private// key** file and **the //public// key** file, linked by a special kind of password called **the passphrase**, that can be used instead of a standard password to connect securely from one server to another server |
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| ssh keys have to be configured properly (a few easy steps), and are **very convenient** because: | ssh keys have to be configured properly (a few easy steps), and are **very convenient** because: |
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| * **They** usually **don't expire!**\\ You don't have to change them (except in some extra secure computing centers like TGCC) and you can keep them for years | * Contrary to passwords, **they usually don't expire!**\\ You don't have to change ssh keys (except in some extra secure computing centers like TGCC) and you can keep them for years |
| * **They don't depend on the accounts and the passwords of the servers where you use them** | * **They don't depend on the accounts and the passwords of the servers where you use them** |
| * You can (and should!) use the same set of ssh keys on several servers: you can then use the same passphrase to access these servers, rather than having to memorize different passwords\\ e.g. if you have your private key on ''account_A'' of ''server_A'' and install the matching public key on ''account_B'' of ''server_B'', etc... you can then use ''ssh'' on ''account_A@server_A'' to access ''account_B@server_B'', ''account_C@server_C'', ... with the same passphrase ! | * You can (and should!) use the same set of ssh keys on several servers: you can then use the **same** passphrase to access all these servers, rather than having to memorize different passwords\\ e.g. if you have your //private// key on ''account_A'' of ''server_A'' and install the matching //public// key on ''account_B'' of ''server_B'', etc... you can then use ''ssh'' on ''account_A@server_A'' to access ''account_B@server_B'', ''account_C@server_C'', ... with the **same** passphrase ! |
| * You can give your public key to somebody and then access their account using your own passphrase (no need to know the password of the other person) | * **You can give your public key** to somebody and then access their account using your own passphrase (no need to know the password of the other person) |
| * The [[https://mesocentre.ipsl.fr/|IPSL Mésocentre ESPRI]] servers can **only** be accessed with a public key and passphrase (the password is not used) | * The [[https://mesocentre.ipsl.fr/|IPSL Mésocentre ESPRI]] servers can **only** be accessed with a public key and passphrase (the password is not used) |
| * By default, ''ssh'' will ask you to type your passphrase each time you connect to a server, but **you can use an //ssh agent// to securely store your passphrase for you**\\ Once you have typed your passphrase in the //ssh agent//, you can connect to all the servers that have your public key without having to type your passphrase! | |
| * ''scp'' (and [[other:win10apps#winscp|WinSCP]]) and the tools using ''ssh'' on your local computer will not ask your passphrase, if they find the passphrase in a running //ssh agent// on the local computer | * By default, ''ssh'' will ask you to type your passphrase each time you connect to a server, but **you can [[other:ssh#using_an_ssh_agent|use an ssh agent]] to securely store your passphrase for you**\\ Once you have typed your passphrase in the //ssh agent//, you can connect to all the servers that have your public key without having to type your passphrase! |
| | * ''scp'' (and [[other:win10apps#winscp|WinSCP]] on Windows) and the tools using ''ssh'' on your local computer will not ask your passphrase, if they find the passphrase in a running //ssh agent// on the local computer |
| * if you use the ''-A'' option ([[other:ssh#most_common_options|agent forwarding]]), the remote server will also //know// (securely) your passphrase, and you will not have to type the passphrase when using ''ssh'', ''scp'' and tools running //over ssh// on the remote server(s) | * if you use the ''-A'' option ([[other:ssh#most_common_options|agent forwarding]]), the remote server will also //know// (securely) your passphrase, and you will not have to type the passphrase when using ''ssh'', ''scp'' and tools running //over ssh// on the remote server(s) |
| * the local //ssh agent// is terminated when you log out of your local computer (or reboot it) | * the local //ssh agent// is terminated when you log out of your local computer (or reboot the computer) |
| ==== Generating ssh keys ==== | ==== Generating ssh keys ==== |
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| === Some common sense advice === | === Some common sense advice === |
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| * **Generate only one pair of private/public keys and use the same pair of keys everywhere!**\\ Put differently, do not generate a different pair of key on each computer/server you use (even if you always use the same passphrase)! | * **Generate only one pair of private/public keys and use the same pair of keys everywhere!**\\ Put differently, do not generate a different pair of key on each computer/server you use (even if you always use the same passphrase)! |
| * Easy to remember passphrase example: "//I love working at LSCE!//" | * Easy to remember passphrase example: "//I love working at LSCE!//" |
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| === Generating keys in a terminal === | === Generating keys in a terminal (Linux and Mac) === |
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| Remember that if you already have a pair of keys, you probably don't want to generate a new pair, unless you have been asked to (e.g. because an old encryption type like //DSA// has been deprecated), or have lost one of the keys, or forgotten your passphrase. If you generate a new pair of keys, you will have to replace the old keys that you were using on all your desktops/laptops, and all the remote servers | If you already have a pair of ssh keys, you probably don't want to generate a new pair, unless you have been asked to (e.g. because an old encryption type like //DSA// has been deprecated), or you have lost one of the keys, or forgotten your passphrase. If you generate a new pair of keys, you will have to replace the old keys that you were using on all your desktops/laptops, and all the remote servers |
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| There are several ways to generate pairs of ssh keys with ''ssh-keygen''. The following one is the one recommended for opening an account on [[https://mesocentre.ipsl.fr/account-opening/|IPSL Mésocentre ESPRI]]. If you open an account on ''spirit'', but already have a public key, just **send your existing public key**! | There are several ways to generate pairs of ssh keys with ''ssh-keygen''. The following one is the one recommended for opening an account on [[https://mesocentre.ipsl.fr/account-opening/|IPSL Mésocentre ESPRI]]. If you open an account on ''spirit'', but already have a public key, just **send your existing public key**! |
| * Accept the default path and key name | * Accept the default path and key name |
| * <wrap em>Do not specify an empty passphrase!</wrap> | * <wrap em>Do not specify an empty passphrase!</wrap> |
| * This will generate two text //key// files in a sub-directory of your account (''~/.ssh/'' on Linux, ''C:\Users\my_login\.ssh\'' on Windows 10): | * Note: ''ssh-keygen -t ed25519'' will also work on Windows! But then you will still have to [[other:putty_conf#converting_existing_ssh_keys_with_puttygen|convert the generated private key with PuTTYgen]] |
| | * This will generate two text //key// files in the [[other:ssh#configuration_files|ssh configuration directory]]: |
| * The **//private// key**: ''id_ed25519'' | * The **//private// key**: ''id_ed25519'' |
| * Note: on a Linux computer, the private key has to be readable only by you, otherwise ''ssh'' will not work | * Note: on a Linux computer, the private key has to be readable only by you, otherwise ''ssh'' will not work |
| -----END OPENSSH PRIVATE KEY-----</code> | -----END OPENSSH PRIVATE KEY-----</code> |
| * The **//public// key**: ''id_ed25519**.pub**'' | * The **//public// key**: ''id_ed25519**.pub**'' |
| * This is the information that you can share. Note that the ''my_login@my_machine'' at the end of the line is just some information about who generated the keys, and where, and can be removed or replaced by something more informative | * This is the //key// that **you can share**, or that you have to send when opening an account on [[https://mesocentre.ipsl.fr/account-opening/|IPSL Mésocentre ESPRI]]. |
| | * Note that the ''my_login@my_machine'' string at the end of the line is just some information about who generated the keys, and where, and can be removed or replaced by something more informative |
| * <code> > cat id_ed25519.pub | * <code> > cat id_ed25519.pub |
| ssh-ed25519 AAAAC3NzaC1lZDI1NT [ lots of cryptic characters ] Frx8rRFKthpmqRdkXl my_login@my_machine</code> | ssh-ed25519 AAAAC3NzaC1lZDI1NT [ lots of cryptic characters ] Frx8rRFKthpmqRdkXl my_login@my_machine</code> |
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| === Generating or importing keys with PuTTY on a Windows computer === | === Generating or importing keys with PuTTY (Windows) === |
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| Read the //Converting/Creating ssh keys with PuTTYgen// sub-sections of [[other:putty_conf#using_ssh_keys|Using ssh keys]], on the ''PuTTY'' page | Read [[other:putty_conf#converting_existing_ssh_keys_with_puttygen|Converting existing ssh keys with PuTTYgen]], or [[other:putty_conf#creating_ssh_keys_with_puttygen|Creating ssh keys with PuTTYgen]] |
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| ==== Installing ssh keys ==== | ==== Installing ssh keys ==== |
