Edge Requirements
An edge needs network access to two things:
- The Plakar Control Plane, over HTTP or HTTPS.
- The systems and services it is expected to protect.
The Control Plane itself does not need network access to those systems. The edge provides that connectivity when it executes a task.
An edge installs integrations from the Control Plane, so reaching PCP is all it needs to run any integration installed there. It only needs internet access if the systems it protects are on the internet. The exception is the external tools some integrations depend on, described below, which must be installed on the edge host separately.
Operating system
The edge and the integrations it installs are built against glibc, so the edge host must run a Linux distribution with glibc 2.34 or later, such as Ubuntu 22.04 or Debian bookworm. Distributions based on musl, such as Alpine, are not supported.
Integrations that need external tools
Most integrations are agentless. They communicate directly with the resource they manage and do not require additional software on the machine running the task. For example, the Windows VSS integration connects to the Windows host over SSH and needs nothing on the edge beyond the SSH client described in SSH client.
Some integrations such as MongoDB, PostgreSQL and MySQL instead rely on
utilities provided by the vendor. These utilities must be installed on the
machine that executes the task. The
MongoDB integration, for example, uses
mongosh, mongodump, and mongorestore, which must be available in the
PATH of the process running the task.
These utilities are not included in the appliance, and the appliance is not intended to be extended with additional software. Tasks that require external tools should therefore run on an edge where the required tools can be installed.
Install the tools required by the integration on the edge host, then configure the task to run on that edge. When edges run as containers, build a custom image that includes the tools. As deployments grow, edges can be equipped with different sets of tools so that workloads can be distributed to the machines capable of running them.
SSH client
The SFTP and
Windows VSS integrations, along with the
integrations built on VSS such as
Microsoft SQL Server and
Microsoft Active Directory, connect through the
OpenSSH ssh client. It must be installed on any edge that runs their tasks,
whatever the authentication method.
When these integrations authenticate with a private key, the edge loads that key
into its own SSH agent, which runs for as long as the edge does. Private key
authentication therefore also requires ssh-add and ssh-agent, which are part
of the OpenSSH client.
The official edge image includes the OpenSSH client. On a binary host or in a
custom image, install it with the distribution
package, such as openssh-client on Debian and Ubuntu.
An edge without ssh-agent still starts and logs a warning. Tasks that
authenticate with an SSH private key fail on that edge, and every other task
runs normally.