# OS Customization {% hint style="info" %} The instructions on this page only apply to Linux installations. {% endhint %} ## Partitioning The OS will be installed on the first disk. NVME drives will be preferred, if a server has multiple disk types. ### Default Linux Disk Partitions By default, regular Linux installations will have the following partitioning details: **Partitions:** * `/boot`, 4096MB * `/`, using the remaining space on the disk * `swap` is enabled and has a size of 8192MB ### Custom Partitioning During [new server requests](https://docs.i3d.net/api/api_flexmetal#post-v3-flexmetal-servers), it is possible to provide your own partitioning scheme. In the `partitions` field of the OS object, you can customize your Linux partitions by specifying a list of them. Each partition object should have the following fields:
FieldTypeDescriptionExample Value
targetstringThe mount point for the partition/boot
filesystemstringThe filesystem to use for the target. Currently supported types: ext2, ext3, ext4, xfsext4
sizeintThe size of the partition in MB, or -1 for the remaining disk space4096
#### Example ```json { "name": "MyFlexServer", "location": "EU: Rotterdam", "instanceType": "bm7.std.8", "os": { "slug": "ubuntu-2404-lts", "partitions": [ { "target": "/boot", "filesystem": "ext4", "size": 4096 }, { "target": "/", "filesystem": "ext4", "size": -1 }, { "target": "/custom", "filesystem": "ext4", "size": 10240 }, { "target": "swap", "size": 8192 } ] }, "sshKey": [ "ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBIWrzxdeW3hhkejzSfFBFzPzcEBJBGtggOUJpLBCakbqmV/NztCaUoh631Xnk46MFn2snF89tSZZzlp9ySpqW7c= ecdsa-key-example" ], "postInstallScript": "#!/bin/bash\necho \"Hello flex world\" > /tmp/test.txt", "tags": [ "My-tag1", "env:dev" ] } ``` {% hint style="info" %} * The `/` and `/boot` partitions are required and must be defined. * The `size` field is in MB. * The `size` field can be `-1` to use the remaining disk space. * To disable the swap file, omit the `swap` partition from the list of partitions. * Accepted filesystems: `ext2`, `ext3`, `ext4`, `xfs`. * Partitioning does not apply to Talos installations, because Talos does not support customizing partitions. {% endhint %} ## The Linux bootloader ### Default bootloader options During the OS installation process, we apply a specific customization to enable legacy network interface naming. This ensures that network interfaces follow the traditional ethX naming convention for OS install compatibility reasons. The following kernel parameters are set: * **`net.ifnames=0`** Disables predictable network interface names. * **`biosdevname=0`** Disables naming based on BIOS device names. No additional options are configured by default. ### Customizing the bootloader {% hint style="warning" %} Incorrect kernel arguments can prevent the server from booting. Please ensure that you provide valid kernel arguments. {% endhint %} You can provide additional kernel arguments to the bootloader by specifying them in the `kernelParams` field of the OS object when you [request a new server](https://docs.i3d.net/api/api_flexmetal#post-v3-flexmetal-servers). These values will be added to the GRUB configuration file and applied as follows: * Add the kernel parameters to the `GRUB_CMDLINE_LINUX` variable in `/etc/default/grub` * Update the GRUB configuration with `update-grub` (Debian based systems) or `grub2-mkconfig -o /boot/grub/grub.cfg` (RH / Centos based systems) * This generates the `grub.cfg` file and generates the `/boot/grub/grubenv` file #### Example In the `kernelParams` field of the OS object, you can provide a list of custom kernel or GRUB parameters. For example: ```json { "name": "MyFlexServer", "location": "EU: Rotterdam", "instanceType": "bm7.std.8", "os": { "slug": "ubuntu-2404-lts", "kernelParams": [ { "key": "mitigations", "value": "auto,nosmt" }, { "key": "nopti", "value": "" } ], }, "sshKey": [ "ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBIWrzxdeW3hhkejzSfFBFzPzcEBJBGtggOUJpLBCakbqmV/NztCaUoh631Xnk46MFn2snF89tSZZzlp9ySpqW7c= ecdsa-key-example" ], "postInstallScript": "#!/bin/bash\necho \"Hello flex world\" > /tmp/test.txt", "tags": [ "My-tag1", "env:dev" ] } ``` This example disables hyperthreading (on the OS level) and disables Page Table Isolation (PTI) in the kernel. The options added to the GRUB configuration are: `mitigations=auto,nosmt nopti`. {% hint style="info" %} Talos Linux requires special kernel arguments to boot. Please refer to the [Talos installation](https://registry.terraform.io/providers/i3D-net/i3dnet/latest/docs/resources/flexmetal_server) documentation for more details. {% endhint %} --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.i3d.net/compute/flexmetal/os-customization.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.