Merge pull request #1035 from BastilleBSD/zfs-jailed

Support jailing datasets

docs/chapters/zfs-support.rst

@@ -58,3 +58,58 @@ dataset for bastille.
 Bastille will mount the datasets it creates at ``bastille_prefix`` which
 defaults to ``/usr/local/bastille``
 If this is not desirable, you can change it at the top of the config file.
+
+Jailing a Dataset
+-----------------
+
+It is possible to "jail" a dataset. This means mounting a datset into a jail, and being
+able to fully manage it from within the jail.
+
+To add a dataset to a jail, we can run ``bastille zfs TARGET jail pool/dataset /path/inside/jail``. 
+This will mount ``pool/dataset`` into the jail at ``/path/inside/jail`` when the jail is started, and
+unmount and unjail it when the jail is stopped.
+
+You can manually change the path where the dataset will be mounted by ``bastille edit TARGET zfs.conf`` and
+adjusting the path after you have added it, bearing in mind the warning below.
+
+WARNING: Adding or removing datasets to the ``zfs.conf`` file can result in permission errors with your jail. It is
+important that the jail is first stopped before attempting to manually configure this file. The format inside
+the file is simple.
+
+.. code-block:: shell
+
+  pool/dataset /path/in/jail
+  pool/other/dataset /other/path/in/jail
+
+To remove a dataset from being jailed, we can run ``bastille zfs TARGET unjail pool/dataset``.
+
+Template Approach
+^^^^^^^^^^^^^^^^^
+
+While it is possible to "jail" a dataset using a template, it is a bit more "hacky" than the above apporach.
+Below is a template that you can use that will add the necessary bits to the ``jail.conf`` file to "jail" a 
+dataset.
+
+.. code-block:: shell
+
+  ARG JAIL_NAME
+  ARG DATASET
+  ARG MOUNT
+
+  CONFIG set allow.mount
+  CONFIG set allow.mount.devfs
+  CONFIG set allow.mount.zfs
+  CONFIG set enforce_statfs 1
+
+  CONFIG set "exec.created += '/sbin/zfs jail ${JAIL_NAME} ${DATASET}'"
+  CONFIG set "exec.start += '/sbin/zfs set mountpoint=${MOUNT} ${DATASET}'"
+
+  RESTART
+
+  CONFIG set "exec.prestop += 'jexec -l -U root ${JAIL_NAME} /sbin/zfs umount ${DATASET}'"
+  CONFIG set "exec.prestop += '/sbin/zfs unjail ${JAIL_NAME} ${DATASET}'"
+
+  RESTART
+
+This template can be applied using ``bastille template TARGET project/template --arg DATASET=zpool/dataset --arg MOUNT=/path/inside/jail``.
+We do not need the ``JAIL_NAME`` arg, as it will be auto-filled from the supplied ``TARGET`` name.

usr/local/share/bastille/start.sh

@@ -186,6 +186,16 @@ for _jail in ${JAILS}; do
     # Start jail
     jail ${OPTION} -f "${bastille_jailsdir}/${_jail}/jail.conf" -c "${_jail}"
 
+    # Add ZFS jailed datasets
+    if [ -s "${bastille_jailsdir}/${_jail}/zfs.conf" ]; then
+        while read _dataset _mount; do
+            zfs set jailed=on "${_dataset}"
+            zfs jail ${_jail} "${_dataset}"
+            jexec -l -U root "${_jail}" zfs set mountpoint="${_mount}" "${_dataset}"
+            jexec -l -U root "${_jail}" zfs mount "${_dataset}" 2>/dev/null
+        done < "${bastille_jailsdir}/${_jail}/zfs.conf"
+    fi
+
     # Add rctl limits
     if [ -s "${bastille_jailsdir}/${_jail}/rctl.conf" ]; then
         while read _limits; do
@@ -215,4 +225,4 @@ for _jail in ${JAILS}; do
     bastille_running_jobs "${bastille_process_limit}"
 	
 done
-wait
+wait

usr/local/share/bastille/stop.sh

@@ -126,6 +126,14 @@ for _jail in ${JAILS}; do
         bastille limits "${_jail}" clear
     fi
 
+    # Unmount any jailed ZFS datasets
+    if [ -s "${bastille_jailsdir}/${_jail}/zfs.conf" ]; then
+        while read _dataset _mount; do
+            jexec -l -U root "${_jail}" zfs umount "${_dataset}"
+            zfs unjail "${_jail}" "${_dataset}"
+        done < "${bastille_jailsdir}/${_jail}/zfs.conf"
+    fi
+
     # Stop jail
     jail ${OPTION} -f "${bastille_jailsdir}/${_jail}/jail.conf" -r "${_jail}"
 

usr/local/share/bastille/zfs.sh

@@ -33,7 +33,10 @@
 . /usr/local/share/bastille/common.sh
 
 usage() {
-    error_notify "Usage: bastille zfs TARGET [set|get|snap|destroy_snap|df|usage] [key=value|date]"
+    error_notify "Usage: bastille zfs TARGET [destroy_snap|df|get|set|(snap|snapshot)|usage] [key=value|date]"
+    error_notify "                           [jail pool/dataset /jail/path]"
+    error_notify "                           [unjail pool/dataset]"
+
     cat << EOF
 	
     Options:
@@ -44,42 +47,127 @@ EOF
     exit 1
 }
 
+zfs_jail_dataset() {
+
+    info "\n[${_jail}]:"
+    
+    # Exit if MOUNT or DATASET is empty
+    if [ -z "${MOUNT}" ] || [ -z "${DATASET}" ]; then
+        usage
+    # Exit if datset does not exist
+    elif ! zfs list "${DATASET}" >/dev/null 2>/dev/null; then
+        error_exit "[ERROR]: Dataset does not exist: ${DATASET}"
+    fi
+
+    # Ensure dataset is not already present in *zfs.conf*
+    if grep -hoqsw "${DATASET}" ${bastille_jailsdir}/*/zfs.conf; then
+        error_exit "[ERROR]: Dataset already assigned."
+    fi
+    # Validate jail state
+    check_target_is_stopped "${_jail}" || if [ "${AUTO}" -eq 1 ]; then
+        bastille stop "${_jail}"
+    else 
+        error_notify "Jail is running."
+        error_exit "Use [-a|--auto] to auto-stop the jail."
+    fi
+
+    # Add necessary config variables to jail
+    bastille config ${_jail} set enforce_statfs 1 >/dev/null
+    bastille config ${_jail} set allow.mount >/dev/null
+    bastille config ${_jail} set allow.mount.devfs >/dev/null
+    bastille config ${_jail} set allow.mount.zfs >/dev/null
+
+    # Add dataset to zfs.conf
+    echo "${DATASET} ${MOUNT}" >> "${bastille_jailsdir}/${_jail}/zfs.conf"
+
+    if [ "${AUTO}" -eq 1 ]; then
+        bastille start "${_jail}"
+    fi
+}
+
+zfs_unjail_dataset() {
+
+    info "\n[${_jail}]:"
+
+    # Exit if DATASET is empty
+    if [ -z "${DATASET}" ]; then
+        usage
+    # Warn if datset does not exist
+    elif ! zfs list "${DATASET}" >/dev/null 2>/dev/null; then
+        warn "[WARNING]: Dataset does not exist: ${DATASET}"
+    fi
+
+    # Validate jail state
+    check_target_is_stopped "${_jail}" || if [ "${AUTO}" -eq 1 ]; then
+        bastille stop "${_jail}"
+    else 
+        error_notify "Jail is running."
+        error_exit "Use [-a|--auto] to auto-stop the jail."
+    fi
+
+    # Remove dataset from zfs.conf
+    if ! grep -hoqsw "${DATASET}" ${bastille_jailsdir}/${_jail}/zfs.conf; then
+        error_exit "[ERROR]: Dataset not present in zfs.conf."
+    else
+        sed -i '' "\#.*${DATASET}.*#d" "${bastille_jailsdir}/${_jail}/zfs.conf"
+    fi
+
+    if [ "${AUTO}" -eq 1 ]; then
+        bastille start "${_jail}"
+    fi
+}
+
 zfs_snapshot() {
+    info "\n[${_jail}]:"
     # shellcheck disable=SC2140
     zfs snapshot -r "${bastille_zfs_zpool}/${bastille_zfs_prefix}/jails/${_jail}"@"${TAG}"
 }
 
 zfs_destroy_snapshot() {
+    info "\n[${_jail}]:"
     # shellcheck disable=SC2140
     zfs destroy -r "${bastille_zfs_zpool}/${bastille_zfs_prefix}/jails/${_jail}"@"${TAG}"
 }
 
 zfs_set_value() {
+    info "\n[${_jail}]:"
     zfs "${ATTRIBUTE}" "${bastille_zfs_zpool}/${bastille_zfs_prefix}/jails/${_jail}"
 }
 
 zfs_get_value() {
+    info "\n[${_jail}]:"
     zfs get "${ATTRIBUTE}" "${bastille_zfs_zpool}/${bastille_zfs_prefix}/jails/${_jail}"
 }
 
 zfs_disk_usage() {
+    info "\n[${_jail}]:"
     zfs list -t all -o name,used,avail,refer,mountpoint,compress,ratio -r "${bastille_zfs_zpool}/${bastille_zfs_prefix}/jails/${_jail}"
 }
 
-
 # Handle options.
+AUTO=0
 while [ "$#" -gt 0 ]; do
     case "${1}" in
         -h|--help|help)
             usage
             ;;
+        -a|--auto)
+            AUTO=1
+            shift
+            ;;
         -x|--debug)
             enable_debug
             shift
             ;;
-        -*)
-            error_notify "[ERROR]: Unknown Option: \"${1}\""
-            usage
+        -*) 
+            for _opt in $(echo ${1} | sed 's/-//g' | fold -w1); do
+                case ${_opt} in
+                    a) AUTO=1 ;;
+                    x) enable_debug ;;
+                    *) error_exit "[ERROR]: Unknown Option: \"${1}\"" ;; 
+                esac
+            done
+            shift
             ;;
         *)
             break
@@ -87,7 +175,7 @@ while [ "$#" -gt 0 ]; do
     esac
 done
 
-if [ "$#" -lt 2 ]; then
+if [ "$#" -lt 2 ] || [ "$#" -gt 4 ]; then
     usage
 fi
 
@@ -111,21 +199,7 @@ for _jail in ${JAILS}; do
 
     (
 
-    info "\n[${_jail}]:"
-
     case "${ACTION}" in
-        set)
-            ATTRIBUTE="${3}"
-            zfs_set_value
-            ;;
-        get)
-            ATTRIBUTE="${3}"
-            zfs_get_value
-            ;;
-        snap|snapshot)
-            TAG="${3}"
-            zfs_snapshot
-            ;;
         destroy_snap|destroy_snapshot)
             TAG="${3}"
             zfs_destroy_snapshot
@@ -133,6 +207,27 @@ for _jail in ${JAILS}; do
         df|usage)
             zfs_disk_usage
             ;;
+        get)
+            ATTRIBUTE="${3}"
+            zfs_get_value
+            ;;
+        jail)
+            DATASET="${3}"
+            MOUNT="${4}"
+            zfs_jail_dataset
+            ;;
+        unjail)
+            DATASET="${3}"
+            zfs_unjail_dataset
+            ;;
+        set)
+            ATTRIBUTE="${3}"
+            zfs_set_value
+            ;;
+        snap|snapshot)
+            TAG="${3}"
+            zfs_snapshot
+            ;;
         *)
             usage
             ;;
@@ -143,4 +238,4 @@ for _jail in ${JAILS}; do
     bastille_running_jobs "${bastille_process_limit}"
 	
 done
-wait
+wait