Installing Nex

All of the functionality you need for Nex is conveniently wrapped up in a single command line tool. To install it, enter the following command in a terminal:

curl -sSf | sh

Depending on your operating system and user privileges, you may need to change sh to sudo sh so the script can place the nex binary in your path.

If you're not comfortable running this command, you can manually install Nex by downloading the latest version from the releases page and simply place the nex binary somewhere in your path.

Note that while the nex binary can be run on any operating system, some node functionality may only available on 64-bit Linux because of the requirements dictated by Firecracker. Also note that running Linux inside docker won't satisfy those requirements.

Once you've installed it, you should be able to check the CLI version with nex version. After you're able to get the help banner and version from nex, you can move on to the next step in this guide.

Performing the Preflight Check

Starting a Nex node can involve the use of the Linux kernel, the firecracker binary, CNI configuration files, an ext4 root file system, machine configuration, and a handful of other things. That's a lot to keep track of, so Nex has conveniently provided a preflight check. Before you can run a preflight check, however, you need to create a node configuration file.

Creating a Node Configuration

The easiest way to create a node configuration file is to copy one from the Nex examples folder, such as the simple.json file, which contains the following JSON:

    "machine_pool_size": 1,
    "cni": {
        "network_name": "fcnet",
        "interface_name": "veth0"
    "machine_template": {
        "vcpu_count": 1,
        "memsize_mib": 256
    "tags": {
        "simple": "true"

Note that if you do end up using /tmp/wd as your resource directory, all of that will go away after a reboot and you'll have to run a preflight check again.

This configuration file will look for a linux kernel file (vmlinux) and a root file system (rootfs.ext4) in the default resource directory. You can override either of these filenames by supplying the kernel_file or rootfs_file fields.

Put this configuration file anywhere you like, but preflight will check ./config.json by default. For each dependency preflight doesn't find, it can create default configuration files and download missing dependencies such as the firecracker binary, a Linux kernel, and our vetted root file system.

After you've run preflight and it downloaded all of the missing components, run it one more time to make sure your output looks similar to what is shown below. There should be a green checkmark for each of the checklist items. Make sure everything checks out before continuing.

$ nex node preflight --config=../examples/nodeconfigs/simple.json
Validating - Required CNI Plugins [/opt/cni/bin]
	✅ Dependency Satisfied - /opt/cni/bin/host-local [host-local CNI plugin]
	✅ Dependency Satisfied - /opt/cni/bin/ptp [ptp CNI plugin]
	✅ Dependency Satisfied - /opt/cni/bin/tc-redirect-tap [tc-redirect-tap CNI plugin]

Validating - Required binaries [/usr/local/bin]
	✅ Dependency Satisfied - /usr/local/bin/firecracker [Firecracker VM binary]

Validating - CNI configuration requirements [/etc/cni/conf.d]
	✅ Dependency Satisfied - /etc/cni/conf.d/fcnet.conflist [CNI Configuration]

Validating - User provided files []
	✅ Dependency Satisfied - /tmp/wd/vmlinux [VMLinux Kernel]
	✅ Dependency Satisfied - /tmp/wd/rootfs.ext4 [Root Filesystem Template]

With a running NATS server and a passing pre-flight checklist, you're ready to start running workloads on NATS!

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