bvmctl

#!/bin/sh

set -e -u

BVM_PATH=$(dirname $(realpath $0))

DEFAULT_NETWORK=bridge0
DEFAULT_CORES=1
DEFAULT_MEMORY=1024
DEFAULT_OSTYPE=freebsd

error()
{
    echo "bvmctl: $@"
    exit 1
}

usage()
{
    cat <<EOF

Usage: bvmctl [ACTION] [OPTION...]

Actions:

    activate [FS]           activate ZFS filesystem for bvm management
    list                    list virtual machines
    create [VM]             create virtual machine
    destroy [VM]            destroy virtual machine
    set [VM] [KEY] [VALUE]  set property
    disk [VM] [SIZE]        add disk to virtual machine (size in GBs)
    svinstall [VM] [SVDIR]  install runit service in SVDIR
    exists [VM]             check if virtual machine exists

Properties:

    network  list of network bridges (bridge0,bridge1/00:00:00:00:00:00,...)
    cores    number of assigned cores
    memory   assigned memory in MBs
    ostype   freebsd | centos7 | debian7 | debian8 | debian9

EOF
}

get_vm_root_fs()
{
    zfs get -H -o name -s local bvm:active | head -n 1
}

check_property()
{
    [ "$1" = "network" ] && return 0
    [ "$1" = "cores"   ] && return 0
    [ "$1" = "memory"  ] && return 0
    [ "$1" = "ostype"  ] && return 0

    error "invalid property $1."
}

perform_activate()
{
    local _vm_root_fs=$(get_vm_root_fs)

    if [ -n "${_vm_root_fs}" ]; then
        error "file system already active (${_vm_root_fs})."
        return 1
    fi

    _vm_root_fs="$1"

    zfs create -o canmount=off "${_vm_root_fs}"
    zfs set bvm:active=on "${_vm_root_fs}"
}

perform_set()
{
    local _vm_name="$1"
    local _property="$2"
    local _value="$3"

    check_property ${_property}

    if [ $(get_vm_root_fs | wc -l) -ne 1 ]; then
        error "filesystem not properly configured."
    fi

    local _vm_root_fs=$(get_vm_root_fs)

    local _vm_fs="${_vm_root_fs}/${_vm_name}"

    zfs set bvm:${_property}=${_value} ${_vm_fs}
}

perform_get()
{
    local _vm_name="$1"
    local _property="$2"

    check_property ${_property}

    if [ $(get_vm_root_fs | wc -l) -ne 1 ]; then
        error "filesystem not properly configured."
    fi

    local _vm_root_fs=$(get_vm_root_fs)

    local _vm_fs="${_vm_root_fs}/${_vm_name}"

    zfs get bvm:${_property} ${_vm_fs}
}

perform_list()
{
    if [ $(get_vm_root_fs | wc -l) -ne 1 ]; then
        error "filesystem not properly configured."
    fi

    local _vm_root_fs=$(get_vm_root_fs)

    zfs list -d 1 -H -o name ${_vm_root_fs} | sed -e "s@${_vm_root_fs}/@@" | grep -v "/"
}

perform_create()
{
    local _vm_name="$1"

    if [ $(get_vm_root_fs | wc -l) -ne 1 ]; then
        error "filesystem not properly configured."
    fi

    local _vm_root_fs=$(get_vm_root_fs)

    local _vm_fs="${_vm_root_fs}/${_vm_name}"

    zfs create -o canmount=off ${_vm_root_fs}/${_vm_name}

    zfs set bvm:network=${DEFAULT_NETWORK} ${_vm_fs}
    zfs set bvm:cores=${DEFAULT_CORES}     ${_vm_fs}
    zfs set bvm:memory=${DEFAULT_MEMORY}   ${_vm_fs}
    zfs set bvm:ostype=${DEFAULT_OSTYPE}   ${_vm_fs}
}

perform_destroy()
{
    local _vm_name="$1"

    if [ $(get_vm_root_fs | wc -l) -ne 1 ]; then
        error "filesystem not properly configured."
    fi

    local _vm_root_fs=$(get_vm_root_fs)

    local _vm_fs="${_vm_root_fs}/${_vm_name}"

    zfs destroy -r ${_vm_fs} > /dev/null 2>&1
}

perform_disk()
{
    local _vm_name="$1"
    local _vol_size="$2"

    if [ $(get_vm_root_fs | wc -l) -ne 1 ]; then
        error "filesystem not properly configured."
    fi

    local _vm_root_fs=$(get_vm_root_fs)

    local _vm_fs="${_vm_root_fs}/${_vm_name}"

    [ -n "${_vol_size}" ] || error "invalid volume size."

    local _index=0

    while true; do
        if [ -e /dev/zvol/${_vm_fs}/disk${_index} ]; then
            _index=$((${_index} + 1))
        else
            break
        fi
    done

    zfs create -b 16K -o volmode=dev -V ${_vol_size}G -o compression=lz4 ${_vm_fs}/disk${_index}
}

perform_svinstall()
{
    local _vm_name="$1"
    local _svdir="$2"

    local _service=${_svdir}/${_vm_name}

    mkdir -p ${_service}

    cat << EOF > ${_service}/run
#!/bin/sh
exec 2>&1
exec ${BVM_PATH}/bvm exec -n \$(basename \$(pwd))
EOF

    chmod 755 ${_service}/run

    mkdir -p ${_service}/log
    cat << EOF > ${_service}/log/run
#!/bin/sh

mkdir -p main
exec chpst svlogd -tt ./main
EOF

    chmod 755 ${_service}/log/run

    cat << EOF > ${_service}/finish
#!/bin/sh

exec 2>&1
exec ${BVM_PATH}/bvm finish -n \$(basename \$(pwd))
EOF

    chmod 755 ${_service}/finish
}

perform_exists()
{
    local _vm_name="$1"

    if [ $(get_vm_root_fs | wc -l) -ne 1 ]; then
        error "filesystem not properly configured."
    fi

    local _vm_root_fs=$(get_vm_root_fs)

    local _vm_fs="${_vm_root_fs}/${_vm_name}"

    zfs get -H -o name name ${_vm_fs} > /dev/null 2>&1
}

if [ $# -eq 0 ]; then
    usage
    exit 1
fi

action="$1"

shift

perform_${action} "$@"