20978: Add upgrade note about MaximumPriceFactor.

Arvados-DCO-1.1-Signed-off-by: Tom Clegg <tom@curii.com>

diff --git a/doc/admin/upgrading.html.textile.liquid b/doc/admin/upgrading.html.textile.liquid
index 32b3bf701cf0f82ad46334ab128e1065303082f7..e8441dd5f0f6c3203232d0bcc2985fbbf36c44d6 100644 (file)
--- a/doc/admin/upgrading.html.textile.liquid
+++ b/doc/admin/upgrading.html.textile.liquid
@@ -32,6 +32,12 @@ h2(#main). development main
 
 "previous: Upgrading to 2.7.0":#v2_7_0
 
+h3. Check implications of Containers.MaximumPriceFactor 1.5
+
+When scheduling a container, Arvados now considers using instance types other than the lowest-cost type consistent with the container's resource constraints. If a larger instance is already running and idle, or the cloud provider reports that the optimal instance type is not currently available, Arvados will select a larger instance type, provided the cost does not exceed 1.5x the optimal instance type cost.
+
+This will typically reduce overall latency for containers and reduce instance booting/shutdown overhead, but may increase costs depending on workload and instance availability. To avoid this behavior, configure @Containers.MaximumPriceFactor: 1.0@.
+
 h3. Synchronize keepstore and keep-balance upgrades
 
 The internal communication between keepstore and keep-balance about read-only volumes has changed. After keep-balance is upgraded, old versions of keepstore will be treated as read-only. We recommend upgrading and restarting all keepstore services first, then upgrading and restarting keep-balance.