Chef

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knife ssh

The knife ssh subcommand is used to invoke SSH commands (in parallel) on a subset of nodes within an organization, based on the results of a search query.

Syntax

This subcommand has the following syntax:

$ knife ssh SEARCH_QUERY SSH_COMMAND (options)

Options

Note

Review the list of common options available to this (and all) Knife subcommands and plugins.

This subcommand has the following options:

-a SSH_ATTR, --attribute SSH_ATTR
The attribute that is used when opening the SSH connection. The default attribute is the FQDN of the host. Other possible values include a public IP address, a private IP address, or a hostname.
-A, --forward-agent
Indicates that SSH agent forwarding is enabled.
-C NUM, --concurrency NUM
The number of allowed concurrent connections.
-G GATEWAY, --ssh-gateway GATEWAY
The SSH tunnel or gateway that is used to run a bootstrap action on a machine that is not accessible from the workstation.
-i IDENTITY_FILE, --identity-file IDENTIFY_FILE
The SSH identity file used for authentication. Key-based authentication is recommended.
-m, --manual-list
Indicates that a search query is a space-separated list of servers. If there is more than one item in the list, put quotes around the entire list. For example: --manual-list "server01 server 02 server 03"
--[no-]host-key-verify
Use --no-host-key-verify to disable host key verification. Default setting: --host-key-verify.
OTHER
The shell type. Possible values: interactive, screen, tmux, macterm, or cssh. (csshx is deprecated in favor of cssh.)
-p PORT, --ssh-port PORT
The SSH port.
-P PASSWORD, --ssh-password PASSWORD
The SSH password. This can be used to pass the password directly on the command line. If this option is not specified (and a password is required) Knife will prompt for the password.
SEARCH_QUERY
The search query used to return a list of servers to be accessed using SSH and the specified SSH_COMMAND. This option uses the same syntax as the search sub-command.
SSH_COMMAND
The command that will be run against the results of a search query.
-x USER_NAME, --ssh-user USER_NAME
The SSH user name.

knife.rb Settings

Note

See knife.rb for more information about how to add optional settings to the knife.rb file.

The following knife ssh settings can be added to the knife.rb file:

knife[:concurrency]
Use to add the --concurrency option.
knife[:identity_file]
Use to add the --identity-file option.
knife[:host_key_verify]
Use to add the --[no-]host-key-verify option.
knife[:manual]
Use to add the --manual-list option.
knife[:ssh_attribute]
Use to add the --attribute option.
knife[:ssh_gateway]
Use to add the --ssh-gateway option.
knife[:ssh_password]
Use to add the --ssh-password option.
knife[:ssh_port]
Use to add the --ssh-port option.
knife[:ssh_user]
Use to add the --ssh-user option.

Examples

The following examples show how to use this Knife subcommand:

Find server uptime

To find the uptime of all of web servers running Ubuntu on the Amazon EC2 platform, enter:

$ knife ssh "role:web" "uptime" -x ubuntu -a ec2.public_hostname

to return something like:

ec2-174-129-127-206.compute-1.amazonaws.com  13:50:47 up 1 day, 23:26,  1 user,  load average: 0.25, 0.18, 0.11
ec2-67-202-63-102.compute-1.amazonaws.com    13:50:47 up 1 day, 23:33,  1 user,  load average: 0.12, 0.13, 0.10
ec2-184-73-9-250.compute-1.amazonaws.com     13:50:48 up 16:45,  1 user,  load average: 0.30, 0.22, 0.13
ec2-75-101-240-230.compute-1.amazonaws.com   13:50:48 up 1 day, 22:59,  1 user,  load average: 0.24, 0.17, 0.11
ec2-184-73-60-141.compute-1.amazonaws.com    13:50:48 up 1 day, 23:30,  1 user,  load average: 0.32, 0.17, 0.15

Run the chef-client on all nodes

$ knife ssh 'name:*' 'sudo chef-client'

Force a chef-client run

To force a chef-client run on all of the web servers running Ubuntu on the Amazon EC2 platform, enter:

$ knife ssh "role:web" "sudo chef-client" -x ubuntu -a ec2.public_hostname

to return something like:

ec2-67-202-63-102.compute-1.amazonaws.com   [Fri, 22 Oct 2010 14:18:37 +0000] INFO: Starting Chef Run (Version 0.9.10)
ec2-174-129-127-206.compute-1.amazonaws.com [Fri, 22 Oct 2010 14:18:37 +0000] INFO: Starting Chef Run (Version 0.9.10)
ec2-184-73-9-250.compute-1.amazonaws.com    [Fri, 22 Oct 2010 14:18:38 +0000] INFO: Starting Chef Run (Version 0.9.10)
ec2-75-101-240-230.compute-1.amazonaws.com  [Fri, 22 Oct 2010 14:18:38 +0000] INFO: Starting Chef Run (Version 0.9.10)
ec2-184-73-60-141.compute-1.amazonaws.com   [Fri, 22 Oct 2010 14:18:38 +0000] INFO: Starting Chef Run (Version 0.9.10)
ec2-174-129-127-206.compute-1.amazonaws.com [Fri, 22 Oct 2010 14:18:39 +0000] INFO: Chef Run complete in 1.419243 seconds
ec2-174-129-127-206.compute-1.amazonaws.com [Fri, 22 Oct 2010 14:18:39 +0000] INFO: cleaning the checksum cache
ec2-174-129-127-206.compute-1.amazonaws.com [Fri, 22 Oct 2010 14:18:39 +0000] INFO: Running report handlers
ec2-174-129-127-206.compute-1.amazonaws.com [Fri, 22 Oct 2010 14:18:39 +0000] INFO: Report handlers complete
ec2-67-202-63-102.compute-1.amazonaws.com   [Fri, 22 Oct 2010 14:18:39 +0000] INFO: Chef Run complete in 1.578265 seconds
ec2-67-202-63-102.compute-1.amazonaws.com   [Fri, 22 Oct 2010 14:18:39 +0000] INFO: cleaning the checksum cache
ec2-67-202-63-102.compute-1.amazonaws.com   [Fri, 22 Oct 2010 14:18:39 +0000] INFO: Running report handlers
ec2-67-202-63-102.compute-1.amazonaws.com   [Fri, 22 Oct 2010 14:18:39 +0000] INFO: Report handlers complete
ec2-184-73-9-250.compute-1.amazonaws.com    [Fri, 22 Oct 2010 14:18:40 +0000] INFO: Chef Run complete in 1.638884 seconds
ec2-184-73-9-250.compute-1.amazonaws.com    [Fri, 22 Oct 2010 14:18:40 +0000] INFO: cleaning the checksum cache
ec2-184-73-9-250.compute-1.amazonaws.com    [Fri, 22 Oct 2010 14:18:40 +0000] INFO: Running report handlers
ec2-184-73-9-250.compute-1.amazonaws.com    [Fri, 22 Oct 2010 14:18:40 +0000] INFO: Report handlers complete
ec2-75-101-240-230.compute-1.amazonaws.com  [Fri, 22 Oct 2010 14:18:40 +0000] INFO: Chef Run complete in 1.540257 seconds
ec2-75-101-240-230.compute-1.amazonaws.com  [Fri, 22 Oct 2010 14:18:40 +0000] INFO: cleaning the checksum cache
ec2-75-101-240-230.compute-1.amazonaws.com  [Fri, 22 Oct 2010 14:18:40 +0000] INFO: Running report handlers
ec2-75-101-240-230.compute-1.amazonaws.com  [Fri, 22 Oct 2010 14:18:40 +0000] INFO: Report handlers complete
ec2-184-73-60-141.compute-1.amazonaws.com   [Fri, 22 Oct 2010 14:18:40 +0000] INFO: Chef Run complete in 1.502489 seconds
ec2-184-73-60-141.compute-1.amazonaws.com   [Fri, 22 Oct 2010 14:18:40 +0000] INFO: cleaning the checksum cache
ec2-184-73-60-141.compute-1.amazonaws.com   [Fri, 22 Oct 2010 14:18:40 +0000] INFO: Running report handlers
ec2-184-73-60-141.compute-1.amazonaws.com   [Fri, 22 Oct 2010 14:18:40 +0000] INFO: Report handlers complete

Run a command based on search query

To query for all nodes that have the “webserver” role and then use SSH to run the command “sudo chef-client”, enter:

$ knife ssh "role:webserver" "sudo chef-client"

Upgrade all nodes

$ knife ssh name:* "sudo aptitude upgrade -y"

Specify the shell type

To specify the shell type used on the nodes returned by a search query:

$ knife ssh roles:opscode-omnitruck macterm

where screen is one of the following values: cssh, interactive, macterm, screen, or tmux. If the node does not have the shell type installed, Knife will return an error similar to the following:

you need the rb-appscript gem to use knife ssh macterm.
`(sudo) gem    install rb-appscript` to install
ERROR: LoadError: cannot load such file -- appscript