1 files changed, 21 insertions, 18 deletions
diff --git a/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/component/TaskContext.java b/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/component/TaskContext.java
index cee2dc9b66b..2d94db3d96e 100644
--- a/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/component/TaskContext.java
+++ b/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/component/TaskContext.java
@@ -1,26 +1,29 @@
 // Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.node.admin.component;
 
-import java.nio.file.FileSystem;
-import java.util.EnumSet;
 import java.util.logging.Logger;
 
 public interface TaskContext {
-    enum Cloud { YAHOO, AWS }
-    Cloud cloud();
+    /**
+     * Record a system modification. IdempotentTask is supposed to converge the system (files,
+     * directory permission, iptable rules, etc) to some wanted state. It is especially important
+     * to produce a truthful log of system changes to understand what may or may not be going on.
+     *
+     * All tasks should:
+     *  1. Record any and all modifications to the system
+     *  2. Avoid recording system interactions that does not actually change the system.
+     *  3. Record system modifications as early as possible and preferably before they are
+     *     performed (sometimes this is not possible).
+     *
+     * @param logger Used to log the modification to help locate the source of the modification.
+     * @param description Description of the modification, e.g. "Changing owner of /foo from alice
+     *                    to bob".
+     */
+    void recordSystemModification(Logger logger, String description);
 
-    enum Role { TENANT_DOCKER_HOST, CONFIG_SERVER_DOCKER_HOST }
-    EnumSet<Role> roles();
-    default boolean hasRole(Role role) {
-        return roles().contains(role);
-    }
-
-    FileSystem fileSystem();
-
-    void logSystemModification(Logger logger, String actionDescription);
-    default void logSystemModification(Logger logger, String format, String... args) {
-        logSystemModification(logger, String.format(format, (Object[]) args));
-    }
-
-    default boolean executeSubtask(IdempotentTask task) { return false; }
+    /**
+     * Execute a task as a child of this task, and with its own sub-TaskContext. Please  avoid
+     * excessive task hierarchies.
+     */
+    boolean executeSubtask(IdempotentTask task);
 }