+ <para>When queuing a new job, control how to deal with already
+ queued jobs. Takes one of <literal>fail</literal>,
+ <literal>replace</literal>,
+ <literal>replace-irreversibly</literal>,
+ <literal>isolate</literal>,
+ <literal>ignore-dependencies</literal>,
+ <literal>ignore-requirements</literal> or
+ <literal>flush</literal>. Defaults to
+ <literal>replace</literal>, except when the
+ <command>isolate</command> command is used which implies the
+ <literal>isolate</literal> job mode.</para>
+
+ <para>If <literal>fail</literal> is specified and a requested
+ operation conflicts with a pending job (more specifically:
+ causes an already pending start job to be reversed into a stop
+ job or vice versa), cause the operation to fail.</para>
+
+ <para>If <literal>replace</literal> (the default) is
+ specified, any conflicting pending job will be replaced, as
+ necessary.</para>
+
+ <para>If <literal>replace-irreversibly</literal> is specified,
+ operate like <literal>replace</literal>, but also mark the new
+ jobs as irreversible. This prevents future conflicting
+ transactions from replacing these jobs. The jobs can still be
+ cancelled using the <command>cancel</command> command.</para>
+
+ <para><literal>isolate</literal> is only valid for start
+ operations and causes all other units to be stopped when the
+ specified unit is started. This mode is always used when the
+ <command>isolate</command> command is used.</para>
+
+ <para><literal>flush</literal> will cause all queued jobs to
+ be canceled when the new job is enqueued.</para>
+
+ <para>If <literal>ignore-dependencies</literal> is specified,
+ then all unit dependencies are ignored for this new job and
+ the operation is executed immediately. If passed, no required
+ units of the unit passed will be pulled in, and no ordering
+ dependencies will be honored. This is mostly a debugging and
+ rescue tool for the administrator and should not be used by
+ applications.</para>
+
+ <para><literal>ignore-requirements</literal> is similar to
+ <literal>ignore-dependencies</literal> but only causes the
+ requirement dependencies to be ignored, the ordering
+ dependencies will still be honoured.</para>