Use this task in a build or release pipeline to copy files from a source folder to a target folder on a remote machine over SSH. This task allows you to connect to a remote machine using SSH and copy files matching a set of minimatch patterns from specified source folder to target folder on the remote machine. Ssh-copy-id does a couple of things (read the man page for details), but the most important thing it does is append the contents of your local public key file to a remote file called authorizedkeys. You could do this yourself by opening the key file with a text editor and pasting the contents in the Kitty terminal.
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Contents Setting up public key authenticationKey based authentication in SSH is called. The purpose of ssh-copy-id is to make setting up public key authentication easier. The process is as follows. Generate an SSH KeyWith, an SSH key is created using. In the simplest form, just run ssh-keygen and answer the questions. The following example illustates this.
# ssh-keygenGenerating public/private rsa key pair.Enter file in which to save the key (/home/ylo/.ssh/idrsa): mykeyEnter passphrase (empty for no passphrase):Enter same passphrase again:Your identification has been saved in mykey.Your public key has been saved in mykey.pub.The key fingerprint is:SHA256:GKW7yzA1J1qkr1Cr9MhUwAbHbF2NrIPEgZXeOUOz3Us ylo@klarThe key's randomart image is:+-RSA 2048-+. o.o.+B + oo.+.o.Oo.+E B.S. o. =. + = o + = =.
+ o o +-SHA256-+#Creating a key pair (public key and private key) only takes a minute. The key files are usually stored in the /.ssh directory. Copy the key to a serverOnce an SSH key has been created, the ssh-copy-id command can be used to install it as an on the server. Once the key has been authorized for SSH, it grants access to the server without a password.Use a command like the following to copy SSH key: ssh-copy-id -i /.ssh/mykey user@hostThis logs into the server host, and copies keys to the server, and configures them to grant access by adding them to the file.
The copying may ask for a password or other authentication for the server.Only the public key is copied to the server. The private key should never be copied to another machine. Test the new keyOnce the key has been copied, it is best to test it: ssh -i /.ssh/mykey user@hostThe login should now complete without asking for a password. Note, however, that the command might ask for the passphrase you specified for the key. TroubleshootingThere are a number of reasons why the test might fail:.The server might not be configured to accept public key authentication. Make sure on the server contains PubkeyAuthentication yes.
Remember to restart the process on the server.If trying to login as, the server might not be configured to allow root logins. Make sure /etc/sshdconfig includes PermitRootLogin yes, PermitRootLogin prohibit-password, or without-password. If it is set to forced-commands-only, the key must be manually configured to use a forced command (see command= option in /.ssh/authorizedkeys.Make sure the client allows public key authentication. Check that includes PubkeyAuthentication yes.Try adding -v option to the ssh command used for the test. Read the output to see what it says about whether the key is tried and what authentication methods the server is willing to accept.OpenSSH only allows a maximum of five keys to be tried authomatically. If you have more keys, you must specify which key to use using the -i option to ssh.How ssh-copy-id worksssh-copy-id uses the to connect to the target host and upload the SSH user key.
The command edits the authorizedkeys file on the server. It creates the.ssh directory if it doesn't exist. It creates the authorized keys file if it doesn't exist. Effectively, ssh key copied to server.It also checks if the key already exists on the server.
Unless the -f option is given, each key is only added to the authorized keys file once.It further ensures that the key files have appropriate permissions. Generally, the user's home directory or any file or directory containing keys files should not be writable by anyone else. Otherwise someone else could add new authorized keys for the user and gain access. Private key files should not be readable by anyone else. Some best practices for SSH keysSSH keys are very useful, but can lead to problems if they are not properly managed. They are access credentials just like user names and passwords. If they are not properly removed when people leave or systems are decommissioned, no-one may any longer know who really has access to which systems and data.
Many large organizations have ended up having millions of SSH keys. Use a passphrase when possibleIt is recommended that keys used for single sign-on have a passphrase to prevent use of the key if it is stolen or inadvertatly leaked. The and programs can be used to avoid having to enter the passphrase every time the key is used.Generally all keys used for interactive access should have a passphrase. Keys without a passphrase are useful for fully automated processes.
They allow shell scripts, programs, and management tools to log into servers unattended. This is often used for backups and data transfers between information systems. Add a command restriction when possibleThe copy-id tool does not automatically add command restrictions to keys. Using command restrictions is highly recommended when the key is used for automating operations, such as running a report for fetching some files.
A command restriction is basically a command=' option added to the beginning of the line in the server's file. Managing SSH keysAnyone having more than a few dozen servers is strongly recommended to.
Not managing the keys exposes the organization to substantial risks, including loss of confidentiality, insertion of fraudulent transactions, and outright destruction of systems.The copy-id tool can be dangerous. It can easily accidentally install multiple keys or unintended keys as authorized. The logic for choosing which key to install is convoluted. Extra authorized keys grant permanent access. They can later be used to spread attacks host-to-host, and the more keys there are, the higher the risk. It also violates all.The is a widely used product for managing SSH keys. Command-line optionsThe sample below presents ssh-copy-id command line syntax: ssh-copy-id -f -n -i identity file -p port -o sshoption user@hostnameThe options have the following meaning:-f Don't check if the key is already configured as an authorized key on the server.
This can result in multiple copies of the key in authorizedkeys files.-i Specifies the identity file that is to be copied (default is /.ssh/idrsa). If this option is not provided, this adds all keys listed by ssh-add -L. Note: it can be multiple keys and adding extra authorized keys can easily happen accidentally! If ssh-add -L returns no keys, then the most recently modified key matching /.ssh/id.pub, excluding those matching /.ssh/.-cert.pub, will be used.-n Just print the key(s) that would be installed, without actually installing them.-o sshoption Pass -o sshoption to the SSH client when making the connection.
This can be used for overriding configuration settings for the client. See and the possible configuration options in.-p port Connect to the specifed SSH port on the server, instead of the default port 22.-h or -? Print usage summary. Ssh-copy-id on MacWhile MacOS includes SSH, it does not include ssh-copy-id out of the port. However, according to some sources MacOS 10.12.4 includes it, and presumably newever versions include it as well.You can test whether your Mac has it by opening a terminal window (Finder / Go / Utilities / Terminal) and typing ssh-copy-id.If your system does not have it, there are many ways to install ssh-copy-id Mac version.
Installation using HomebrewTo install it using Homebrew, use the following command. You need to have the brew command installed. Brew install ssh-copy-id Installation from MacPortsThe following command will install it using MacPorts. You need to have the port command installed. Sudo port install openssh +ssh-copy-id Installation using CurlThe following command can be used to install a Mac version directly. Note that as a general rule we do not recommend piping any commands from the network to the shell, like this does. Only use this method if you fully trust the source.
The advantage of this method is that it does not need any special software - curl comes preinstalled.
The ssh-copy-id command (in the openssh-client package and installed by default) does exactly this: ssh-copy-id [email protected] the public key of your default identity (use -i identityfile for other identities) to the remote host.The default identity is your 'standard' ssh key. It consists of two files (public and private key) in your /.ssh directory, normally named identity, idrsa, iddsa, idecdsa or ided25519 (and the same with.pub), depending on the type of key. If you did not create more than one ssh key, you do not have to worry about specifying the identity, ssh-copy-id will just pick it automatically.In case you do not have an identity, you can generate one with the tool ssh-keygen.In addition, if the server uses a port different from the default one ( 22) you should use quotation marks in this way : ssh-copy-id '[email protected] -p '. I like the answer from Marcel. I did not know this command. I've always been using what I had found on the: cat /.ssh/idrsa.pub ssh @ 'cat.ssh/authorizedkeys && echo 'Key copied'I thought to post it here still, because it is a good illustration of what can be achieved in shell code with the power of ssh. But using the ssh-copy-id is definitively a safer way to do it properly!Note that if the folder.ssh does not already exist, the above command will fail.
In addition, it might be better when creating the file to set a minimum possible permission (basically read-write for owner only). Here is a more advanced command: cat /.ssh/idrsa.pub ssh @ 'umask 0077; mkdir -p.ssh; cat.ssh/authorizedkeys && echo 'Key copied'. On Ubuntu you can fetch your keys from Launchpad: ssh-import-id launchpad account nameDetails:. You need a Launchpad account so. After logging in, click the button next to SSH keys:.Paste the contents of your public key file in that field (including comment).
Such a key looks like: ssh-rsa AAAAB3Nza. UyDOFDqJp lekensteynHere, ssh-rsa indicates that the key is a RSA key, AAAAB3Nza. UyDOFDqJp is the actual key and lekensteyn is the comment. Save the key by pressing Import Public Key. If everything went well, your key should now be listed under SSH keys:The package ssh-import-id needs to be installed on the machine which needs to be accessed from remote. This package is installed together with the openssh-server package as it's a recommended package for openssh-server.
After making sure that ssh-import-id has been installed On the client machine, run: ssh-import-id launchpad account nameThis will download the public key from the Launchpad servers over HTTPS which protects you from MITM attacks.On Ubuntu Lucid and before, you can accomplish the same with: wget acount name/+sshkeys -O - /.ssh/authorizedkeys && echo /.ssh/authorizedkeysThe echo command is needed to get an extra newline after the line with the SSH key. Ssh-copy-id does exactly that. I am not sure why some of the other answers here add inaccurate information. The help shows the following: $ ssh-copy-id -hUsage: /usr/bin/ssh-copy-id -h -? -f -n -i identityfile -p port -o.
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user@hostname-f: force mode - copy keys without trying to check if they are already installed-n: dry run - no keys are actually copied-h -?: print this helpI just tried the following on Ubuntu 18.04 client with a CentOS 7.6 server and it worked like a charm. The example shows using a custom port of 2222, and specifying a public key at /.ssh/path-to-rsa.pub $ ssh-copy-id -i /.ssh/path-to-rsa.pub -p 2222 [email protected] running the command, I actually used the -n switch at the end to do a dry run which confirmed that the command will work as intended. Once I confirmed it I ran the command again as above, without the -n switch.
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