Configuring ticrypt Virtual Machines

ticrypt-vm config

This service is one of the most complicated parts of tiCrypt. The configuration options are extensive and require significant configuration.

Parameters for the section ticrypt.vm:

Parameter	Type	Required	Description
`mongodb`	Section	✅	See mongo-ti
`cost-functions`	Section	✅	See cost-fct
`hardware-profiles`	Section	✅	See hardware-profile
`realms`	Section	✅	See tc-realms
`licensing-server-driver`	String		none, firewalld
`reload-freq`	Duration		How often to re-build the rules
`firewalld`	Section		Setup for firewalld driver
`akka.remote.netty.tcp.hostname`			See ticrypt-vm
`akka.remote.netty.tcp.port`			See ticrypt-vm

Parameters for ticrypt.vm.firewalld:

Parameter	Type	Required	Description
`file-access`	String	✅	File where rules are written.

Make sure that file-access option in ticrypt.vm.firewalld matches the mechanism you have to transform rules into firewall access. If using ticrypt-allowedlist service, the file must be /etc/ticrypt/allowedlist.txt.

tiCrypt realms

A realm is a fully independent VM execution environment that has its own:

VM Images: the content of the boot drive used to start the VMs.
Drives: the user drives that store the encrypted data.

Two types of realms are supported as of version 3.1.2: Libvirt and Nutanix.

The realms section specifies realms and includes files for their config. Example:

realms {
    libvirt1 = { include "realms/libvirt1.conf" }
    libvirt2 = { include "realms/libvirt2.conf" }
    nutanix = { include "realms/nutanix.conf" }
}

You can specify as many Libvirt and as many Nutanix realms as you want.

Configuring the two types of realms requires careful, realm-specific explanation. The next sections deal with that.

Both the common and specific parameters should not be in a section since the file is included.

Nutanix Realm Configuration

The Nutanix realm uses a Nutanix Cluster to execute the VMs and to host the VM Drives and Images.

The parameters required by the Nutanix driver depend on an already set-up environment in Nutanix PRISM. In particular, you need to:

Set up an account used by tiCrypt. We suggest the user name ticrypt and a strong password. The account must have enough privileges to create/remove VMs and drives.
Create a network and obtain the network ID.
Create a storage container for drives and obtain the ID.

Parameter	Type	Required	Description
`disabled`	Boolean	✅	Is the realm disabled?
`driver`	nutanix	✅	This is a Nutanix realm
`name`	String	✅	Displayable name of realm
`network-id`	String	✅	The network ID in Nutanix
`drives.storage-container-id`	String	✅	The storage ID
`hostname`	String	✅	The hostname of Nutanix cluster
`port`	Port		The port of PRISM API, default 9440
`username`	String		Defaults to ticrypt
`password`	String	✅	The password of the Nutanix account
`task-poll-freq`	Duration		How often to get task updates
`registration-timeout`	Duration		VM startup timeout
`drives.min-size`	Size		Minimum drive size
`drives.max-size`	Size		Maximum drive size

caution

registration-timeout is somewhat critical. Too short and the VMs do not have enough time to register and get killed.

To debug VMs that do not correctly register, increase registration-timeout and attach a console.

You almost always want to increase drives.max-size. The default value is 32 GiB.

VM Images can only be imported via the Nutanix PRISM interface.

VM Naming Configuration

In addition, Nutanix VMs are automatically prepended with a tag to specify that they are part of tiCrypt. By default, they are named "tc-<name>", but the automatic naming can be changed via the nutanix realm’s config.

In the nutanix realm config:

    vm-name: "tc-<name>"
    vm-desc: "tiCrypt managed VM | Owner: <owner> (<ownerID>) | Brick: <brick> (<brickID>)"

The tags in brackets will be filled with that VM's information, and the following tags can be used:

Tag	Description	Example
`<name>:`	VM name	Nutanix VM 1
`<team>:`	Team name	Tera Insights
`<owner>:`	VM owner’s full name	TiCrypt User
`<ownerID>:`	VM owner’s ID	289f4326-a3a8-49e5-8327-2bdba30d3aba
`<project>:`	Project name	TiCrypt Testing
`<brick>:`	Brick name	Nutanix-CentOS
`<brickID>:`	Brick ID	bdd65456-0f1e-4d29-aa65-fdcc71926431

Drive Naming Configuration

The same mechanism is available for drives on Nutanix.

In the nutanix realm config:

    drive-name: "tc-<name>"
    drive-desc: "tiCrypt managed drive | Owner: <owner> (<ownerID>) | Format: <format>"

The tags in brackets will be filled by that drive’s information, and the following tags can be used:

Tag	Description	Example
`<name>:`	VM name	Nutanix VM 1
`<team>:`	Team name	Tera Insights
`<owner>:`	VM owner’s full name	TiCrypt User
`<ownerID>:`	VM owner’s ID	289f4326-a3a8-49e5-8327-2bdba30d3aba
`<project>:`	Project name	TiCrypt Testing
`<format>:`	Drive format	ext4

Libvirt Realm Configuration

The Libvirt realm uses KVM/QEMU to control the VMs. For this to work, we need:

ticrypt-vm service must have root access to all the VM Host servers. This is accomplished by injecting the RSA-2048 public key of ticrypt-vm into the /root/.ssh/authorized_keys file for each of the VM Hosts.
A distributed file system shared by all the VM Hosts must be set up. The storage must be large enough to accommodate the VM Images, VM Drives, and Libvirt temporary files.

Two independent tasks need to be accomplished for the Libvirt realms to function correctly:

Realm setup
Hardware description

The realm setup is specified in the file included in the realms section of ticrypt-vm. The hardware description goes into ticrypt-vm config file itself.

Configuring the Libvirt Realm

All the parameters go in the included file specified in the realms section.

These parameters should not be part of sections inside the included file.

Parameter	Type	Required	Description
`disabled`	Boolean	✅	Is the realm disabled?
`driver`	livbirt	✅	This is a Libvirt realm
`name`	String	✅	Displayable name of realm
`volumes-pool`	String		Libvirt name for volumes pool
`drives-pool`	String		Libvirt name for drives pool
`bricks-pool`	String		Libvirt name for VM Images
`log-scheduling`	Bool		Debug VM scheduler?
`registration-timeout`	Duration		VM startup timeout
`poll-frequency`	Duration		How often a VM is checked
`network-filter`	String		Default network filter
`drives.lazy-allocation`	on, off	✅	Delay allocation?
`drives.cache`	String		Cache strategy
`drives.min-size`	Size		Minimum drive size
`drives.max-size`	Size		Maximum drive size
`uploads`	Section		Reserved for future use
`scaling`	Section		Reserved for future use

Some notes on the above are in order.

volumes-pool, drives-pool and bricks-pool have default values ticrypt-vm, ticrypt-vm-drives and ticrypt-bricks. Unless you are hosting multiple tiCrypt instances, there is no reason to change the defaults.
registration-timeout cannot be too short since some VMs might not have time to boot and register within the specified time and fail.
network-filter is an obscure feature that needs to be specified only if problems arise. See libvirt source for an in-depth explanation.
You almost always want drives.lazy-allocation=on. This way, you "pay" for the storage only when it is needed.
drives.cache is best left at "default". In general, it is tricky to select. Possible values are:
1. "default": System default caching strategy, may be either "writethrough" or "writeback" depending on the version of qemu-kvm.
2. "writethrough": Host page cache is enabled, but disk write cache is disabled, meaning all writes to the drive are completed only when the data has been committed to the underlying storage. Similar to adding O_DSYNC flag to writes.
3. "writeback": Both the host page cache and disk write cache are enabled. Disk behaves similarly to a raid controller with a RAM cache.
4. "none": Bypasses host page cache entirely. Similar to adding O_DIRECT flag to reads and writes.

Hardware specification preliminaries

There are four main components in VM host hardware configuration:

Curves

Built-in parameterized functions take in the value of a single attribute (e.g. number of VMs, amount of memory used) and return a cost based on that attribute. Used in the construction of Cost Functions.

Cost Functions

Configurable rules determine how much it costs to schedule resources on a specific node. Used to determine if VMs can be scheduled to specific notes, and which node is most optimal.

Hardware Profiles

Descriptions of a hardware configuration. Link together a cost function along with resource information. Assigned to hosts to allow for scheduling and device allocation.

Hosts

Individual machines are used to run client VMs. Hosts are assigned a hardware profile to use for scheduling decisions.

Cost Functions and Hardware Profiles are managed in the ticrypt-vm configuration file, while Hosts are dynamically managed using the tiCrypt user interface.

The types of values used in the description of parameters are:

Type	Example	Description
String	"an example"	String value
Int	42	Whole number value
Bytes	32, 64 MiB, 18 GiB	A number of types with an optional unit
Real	1.0, 1	A real number with an optional decimal place
RealOrBytes	1.0, 32 MiB, 2 GiB	Either a real number or several bytes with unit
Curve	`curve: invalid`	A curve definition
CurveMap	id1: ..., id2: ...	A mapping of IDs to curve definitions
Device	type: "gpu", addr: "02:03.4"	Object containing a device’s type and PCI address
DeviceList	[..., ...]	A List of Device entries

Curves

Curves are configuration objects with a single required string parameter, curve. This refers to one of the following built-in curves which take a single attribute and compute a cost from it. This may be the number of VMs running, the amount of memory being used in bytes, or the number of specific devices in use. Additional parameters may be specified depending on the curve type.

If a curve has multiple values listed for its types, any of those can be used as the value of the curve attribute.

The following parameters are common to all curve types:

Parameter	Type	Required	Default	Description
`scale`	Real		1.0	The scale factor to apply to the curve result.
`max`	Real		None	If specified, any input past this value will return Infinity.

Common Curve Parameters

Constant curve

Types: constant

Always returns a fixed value.

Parameter	Type	Required	Default	Description
`value`	Real		✅	The constant value to return.

Constant Curve Parameters

{ curve: constant, value: 1.0 }

Invalid Curve

Types: invalid

Always returns positive infinity, preventing the VM from being scheduled. Mostly useful in conjunction with the Piecewise Curve.

{ curve: invalid }

Linear Curve

Types: linear

Computes a value from the input based on a line with a given slope and base.

Parameter	Type	Required	Default	Description
`slope`	RealOrBytes		✅	The slope of the line.
`base`	RealOrBytes		✅	The vaule to return when the input is 0.

Linear Curve Parameters

{ curve: linear, slope: 1.0, base: 0.0 }
{ curve: linear, slope: 10.0, base: 5.0 }

Hard-Soft Curve

Types: hard-soft, soft-hard

Creates a mostly continuous piecewise linear curve with a soft and hard cap. The cost ramps up slowly until the input reaches soft, at which the cost ramps up much more quickly until the input reaches hard. After that, the cost is infinite.

Parameter	Type	Default	Description
`soft`	RealOrBytes	✅	The input value at which softAmt should be returned.
`hard`	RealOrBytes	✅	The input value at which hardAmt should be returned.
`softAmt`	Real	1.0	The cost returned when the input value reaches soft.
`hardAmt`	Real	10.0	The cost returned when the input value reaches hard.

Hard-Soft Curve Parameters

Hard-Soft Curve Examples

# Returns 0 when input is 0, 1 when input is 1, 10 when input is 2, infinity when input > 2
{ curve: "hard-soft", soft: 1.0, hard: 2.0 }

# Both of these are equivalent
{ curve: "hard-soft", soft: 32 GiB, hard: 48 GiB, softAmt: 10, hardAmt: 100 }
{ curve: "hard-soft", soft: 32 GiB, hard: 48 GiB, scale: 10.0 }

Unavailable Curve

Types: unavailable

Creates a piecewise curve that returns either 0 if the input is less than or equal to zero, or infinity if the input is greater than zero. This is useful for denoting unavailable resources.

This curve is the default for any devices that do not otherwise have curves associated with them.

Unavailable Curve Examples

{ curve: unavailable }

Piecewise Curve

Aliases: piecewise, low-high, high-low

Returns the result of one of two curves depending on the input value. Allows for more complex piecewise linear curves.

Parameter	Type	Default	Description
`cutoff`	RealOrBytes	✅	The cutoff point for switching from low to high
`low`	Curve	✅	The curve to use when the input is less than or equal to the cutoff
`high`	Curve	✅	The curve to use when the input is greater than the cutoff

Linear Curve Parameters

Piecewise Curve Examples

# Constant cost of 5 up to a hard cutoff when input is 6
{ curve: piecewise, cutoff: 6.0, low: { curve: constant, value: 5}, high: { curve: invalid } }

# Same as a hard-soft with soft = 1, hard = 2, softAmt = 1, hardAmt = 10
{
    curve: piecewise
    cutoff: 1
    low: {
        curve: linear
        slope: 1
        base: 0
    }
    high: {
        curve: piecewise
        cutoff: 2
        low: {
            curve: linear
            slope: 9
            base: -8
        },
        high: {
            curve: invalid
        }
    }
}

# Same as unavailable
{
    curve: piecewise,
    cutoff: 0,
    low: { curve: constant, value: 0 },
    high: { curve: invalid }
}

Cost Functions

Cost Functions are managed in the ticrypt.vm.cost-functions section of ticrypt-vm.conf, which is mapping of cost function IDs to their definition. Cost function definitions have the following structure. See the section Curves for more information about parameters with the type Curve.

Parameter	Type	Default	Description
`name`	String	Same as ID	A human-readable name for the cost function.
`description`	String	Empty	A description of the cost function.
`vms`	Curve	None	Curve used to assign cost based on the number of VMs running.
`vcpus`	Curve	None	Curve used to assess cost based on the number of virtual CPU cores used.
`memory`	Curve	None	Curve used to assign cost based on memory usage in bytes.
`devices`	CurveMap	None	Mapping of device ID to curve for the cost of using devices of that type.
`scale`	Real	1.0	Scaling factor to multiply all costs generated by this function.
`offset`	Real	0.0	Static offset to add to all costs generated by this function. Not affected by the scale.

Cost Function Parameters

Any device types not listed in the devices section will act as if they were defined with the unavailable curve.

A curve should be set for at least one of vms, vcpus, or memory; otherwise, there will be no restriction on VMs using no devices being scheduled to hosts using this cost function. This will cause rapid resource exhaustion.

Examples

Basic Cost Function

ticrypt.vm.cost-functions {
    simple {
        name: "Simple"
        description: "A basic cost function"

        # Add 1 cost per VM scheduled to the VM
        vms: { curve: "linear", slope: 1, base: 0 }

        # VCPUs cost 0.5 each until 8, then 3 each until 16
        vcpus: { curve: "hard-soft", soft: 8, hard: 16, softAmt: 4, hardAmt: 32 }

        # Add 10 cost at 16 GiB of memory, 100 at 32 GiB
        memory: { curve: "hard-soft", soft: 16 GiB, hard: 32 GiB, scale: 10}
        # alternative way to specify the same thing:
        #memory: { curve: "hard-soft", soft: 16 GiB, hard: 32 Gib, softAmt: 10, hardAmt: 100 }
    }
}

Cost Function with GPUs

ticrypt.vm.cost-functions {
    nvidia-gpu {
        name: "GPU Node"
        description: "Used for GPU nodes with the standard configuration"

        # Same as simple
        vms: { curve: "linear", slope: 1, base: 0 }
        vcpus: { curve: "hard-soft", soft: 8, hard: 16, softAmt: 4, hardAmt: 32 }
        memory: { curve: "hard-soft", soft: 16 GiB, hard: 32 GiB, scale: 10}

        # NVidia GPUs cost 1 each, up to a max of 2 used
        devices.nvidia-gpu: { curve: linear, slope: 1, base: 0, max: 2}

        # Extremely high offset so that VMs do not get scheduled here unless there is no
        # other choice
        offset: 100000
    }
}

Cost Functions Using Pools and Includes

.ticrypt-vm.conf

ticrypt.vm.cost-functions {
    pool1 {
        include "cost-functions/pool-common.conf"
        name: "Pool 1"
    }
    pool2 {
        include "cost-functions/pool-common.conf"
        name: "Pool 2"
        # Add a flat 1000 so that hosts in pool 2 will not be used unless the VM could not be
        # scheduled to hosts in pool 1
        offset: 1000
    }
}

cost-functions/pool-common.conf

vms: { curve: "linear", slope: 1, base: 0 }
vcpus: { curve: "hard-soft", soft: 8, hard: 16, softAmt: 4, hardAmt: 32 }
memory: { curve: "hard-soft", soft: 16 GiB, hard: 32 GiB, scale: 10}

Hardware Profiles

Hardware Profiles are defined in the ticrypt.vm.hardware-profiles section in ticrypt-vm.conf. Each Hardware profile should be defined as an ID mapped to a configuration block with the following parameters:

Parameter	Type	Required	Default	Description
`name`	String		Same as ID	A human-readable name for the hardware profile.
`description`	String		Empty	A description of the hardware profile.
`cores`	Int	✅		The number of CPU cores available on the host.
`memory`	Bytes	✅		The amount of memory in bytes available on the host.
`devices`	DeviceList		[]	The PCI devices available for VM use.
`cost-function`	String	✅		The ID of the cost function to use for this profile.

Hardware Profile Parameters

Hardware Profile Examples

ticrypt.vm.hardware-profiles {
    pool1: {
        name: "Pool 1"
        description: "Standard host in pool 1"
        cores: 8
        memory: 32 GiB
        cost-function: "pool1"
    }
    pool2: {
        name: "Pool 2"
        description: "Standard host in pool 2"
        cores: 8
        memory: 32 GiB
        cost-function: "pool2"
    }
    nvidia-gpu-node: {
        name: "NVidia GPU Node"
        description: "Special nodes with NVidia GPUs attached"
        cores: 8
        memory: 32 GiB
        cost-function: nvidia-gpu
        devices = [
            {type: "nvidia-gpu", addr: "0000:01:02.0"}
            # PCI addresses can omit the domain if it is all 0
            {type: "nvidia-gpu", addr: "02:03.0"},
        ]
    }
}

Hosts

Hosts are managed from the tab in the tiCrypt user interface. Administrators can add, enable, disable, and remove hosts from this interface.

Each host’s configuration consists of the following pieces of information:

Name

A descriptive name of the specific host.

URI

The Libvirt connection URI is used to connect to the host. Full documentation on the various URI formats is available at the Libvirt documentation. Some examples include:

Local QEMU Connection:

`qemu:///system`

Remote QEMU Connection:

`qemu+ssh://[user@]host[:port]/system`

Hardware Profile

One of the defined hardware profiles to use for resource and scheduling information.

State

The operational state of the host. Can be one of the following:

Enabled

A connection will be established with the host, and VMs will be scheduled to it.

No Scheduling

A connection will be established with the host, but no new VMs will be scheduled to it. This allows for the management of existing VMs without allowing new VMs. Useful for nodes that need to be brought down gracefully.

Disabled

No connection with the host will be made, and no VMs will be scheduled to it.

Static Address Translation

Optional configuration used if VMs are not networks that are not directly reachable from the tiCrypt server. If needed, an IP address and base port can be specified tiCrypt will then make connections to the specified address when communicating with VMs, with the port determined by the base port plus the last octet of the VM’s IP address.

Setting up Libvirt Pools

If you used the recommended default values for volumes-pool, drives-pool and bricks-pool, there are four pools that need to be set up in libvirt: ticrypt-vm, ticrypt-vm-drives, ticrypt-bricks and ticrypt-vm-snapshot.

In order to define pools, e.g. ticrypt-vm-snapshots, you can:

\`\`\` virsh pool-define-as ticrypt-vm-snapshots dir - - - - "&lt;path/to/pool&gt;" virsh pool-build ticrypt-vm-snapshots virsh pool-start ticrypt-vm-snapshots virsh pool-autostart ticrypt-vm-snapshots \`\`\`

Configuring ticrypt Virtual Machines

tiCrypt realms

Nutanix Realm Configuration

VM Naming Configuration

Drive Naming Configuration

Libvirt Realm Configuration

Configuring the Libvirt Realm

Hardware specification preliminaries

Curves​

Cost Functions​

Hardware Profiles​

Hosts​

Curves

Constant curve​

Invalid Curve​

Linear Curve​

Hard-Soft Curve​

Unavailable Curve​

Piecewise Curve​

Cost Functions

Examples​

Hardware Profiles ​

Hosts​

Name​

URI​

Hardware Profile​

State​

Enabled​

No Scheduling​

Disabled​

Static Address Translation​

Setting up Libvirt Pools

Curves

Cost Functions

Hardware Profiles

Hosts

Constant curve

Invalid Curve

Linear Curve

Hard-Soft Curve

Unavailable Curve

Piecewise Curve

Examples

Hardware Profiles

Hosts

Name

URI

Hardware Profile

State

Enabled

No Scheduling

Disabled

Static Address Translation