Miscellaneous Salt Cloud Options¶

Deploy Script Arguments¶

Custom deploy scripts are unlikely to need custom arguments to be passed to them, but salt-bootstrap has been extended quite a bit, and this may be necessary. script_args can be specified in either the profile or the map file, to pass arguments to the deploy script:

ec2-amazon:
    provider: ec2
    image: ami-1624987f
    size: t1.micro
    ssh_username: ec2-user
    script: bootstrap-salt
    script_args: -c /tmp/

This has also been tested to work with pipes, if needed:

script_args: | head

Selecting the File Transport¶

By default, Salt Cloud uses SFTP to transfer files to Linux hosts. However, if SFTP is not available, or specific SCP functionality is needed, Salt Cloud can be configured to use SCP instead.

file_transport: sftp
file_transport: scp

Sync After Install¶

Salt allows users to create custom modules, grains, and states which can be synchronised to minions to extend Salt with further functionality.

This option will inform Salt Cloud to synchronise your custom modules, grains, states or all these to the minion just after it has been created. For this to happen, the following line needs to be added to the main cloud configuration file:

sync_after_install: all

The available options for this setting are:

modules
grains
states
all

Setting up New Salt Masters¶

It has become increasingly common for users to set up multi-hierarchal infrastructures using Salt Cloud. This sometimes involves setting up an instance to be a master in addition to a minion. With that in mind, you can now lay down master configuration on a machine by specifying master options in the profile or map file.

make_master: True

This will cause Salt Cloud to generate master keys for the instance, and tell salt-bootstrap to install the salt-master package, in addition to the salt-minion package.

The default master configuration is usually appropriate for most users, and will not be changed unless specific master configuration has been added to the profile or map:

master:
    user: root
    interface: 0.0.0.0

Delete SSH Keys¶

When Salt Cloud deploys an instance, the SSH pub key for the instance is added to the known_hosts file for the user that ran the salt-cloud command. When an instance is deployed, a cloud provider generally recycles the IP address for the instance. When Salt Cloud attempts to deploy an instance using a recycled IP address that has previously been accessed from the same machine, the old key in the known_hosts file will cause a conflict.

In order to mitigate this issue, Salt Cloud can be configured to remove old keys from the known_hosts file when destroying the node. In order to do this, the following line needs to be added to the main cloud configuration file:

delete_sshkeys: True

Keeping /tmp/ Files¶

When Salt Cloud deploys an instance, it uploads temporary files to /tmp/ for salt-bootstrap to put in place. After the script has run, they are deleted. To keep these files around (mostly for debugging purposes), the --keep-tmp option can be added:

salt-cloud -p myprofile mymachine --keep-tmp

For those wondering why /tmp/ was used instead of /root/, this had to be done for images which require the use of sudo, and therefore do not allow remote root logins, even for file transfers (which makes /root/ unavailable).

Hide Output From Minion Install¶

By default Salt Cloud will stream the output from the minion deploy script directly to STDOUT. Although this can been very useful, in certain cases you may wish to switch this off. The following config option is there to enable or disable this output:

display_ssh_output: False

Connection Timeout¶

There are several stages when deploying Salt where Salt Cloud needs to wait for something to happen. The VM getting it's IP address, the VM's SSH port is available, etc.

If you find that the Salt Cloud defaults are not enough and your deployment fails because Salt Cloud did not wait log enough, there are some settings you can tweak.

You can tweak these settings globally, per cloud provider, or event per profile definition.

Salt Cloud Cache¶

Salt Cloud can maintain a cache of node data, for supported providers. The following options manage this functionality.

cache_event_strip_fields:
  - password
  - priv_key

SSH Known Hosts¶

Normally when bootstrapping a VM, salt-cloud will ignore the SSH host key. This is because it does not know what the host key is before starting (because it doesn't exist yet). If strict host key checking is turned on without the key in the known_hosts file, then the host will never be available, and cannot be bootstrapped.

If a provider is able to determine the host key before trying to bootstrap it, that provider's driver can add it to the known_hosts file, and then turn on strict host key checking. This can be set up in the main cloud configuration file (normally /etc/salt/cloud) or in the provider-specific configuration file:

known_hosts_file: /path/to/.ssh/known_hosts

If this is not set, it will default to /dev/null, and strict host key checking will be turned off.

It is highly recommended that this option is not set, unless the user has verified that the provider supports this functionality, and that the image being used is capable of providing the necessary information. At this time, only the EC2 driver supports this functionality.

SSH Agent¶

If the ssh key is not stored on the server salt-cloud is being run on, set ssh_agent, and salt-cloud will use the forwarded ssh-agent to authenticate.

ssh_agent: True

File Map Upload¶

The file_map option allows an arbitrary group of files to be uploaded to the target system before running the deploy script. This functionality requires a provider uses salt.utils.cloud.bootstrap(), which is currently limited to the ec2, gce, openstack and nova drivers.

The file_map can be configured globally in /etc/salt/cloud, or in any cloud provider or profile file. For example, to upload an extra package or a custom deploy script, a cloud profile using file_map might look like:

ubuntu14:
  provider: ec2-config
  image: ami-98aa1cf0
  size: t1.micro
  ssh_username: root
  securitygroup: default
  file_map:
    /local/path/to/custom/script: /remote/path/to/use/custom/script
    /local/path/to/package: /remote/path/to/store/package