11305: added kernel and module dependency for docker migration in doc

refs #11305

diff --git a/doc/install/migrate-docker19.html.textile.liquid b/doc/install/migrate-docker19.html.textile.liquid
index 097283be328de2494dc0ce0aedc36f9237e13080..37a9364218b0701dd59d6563c244e4d44bcb60aa 100644 (file)
--- a/doc/install/migrate-docker19.html.textile.liquid
+++ b/doc/install/migrate-docker19.html.textile.liquid
@@ -8,11 +8,12 @@ If you have an existing Arvados installation using Docker 1.9 and wish to update
 
 The @arv-migrate-docker19@ tool converts Docker images stored in Arvados from image format v1 (Docker <= 1.9) to image format v2 (Docker >= 1.10).
 
-Requires Docker running on the local host (can be either 1.9 or 1.10+).
+Requires Docker running on the local host (can be either 1.9 or 1.10+). Linux kernel >= 3.18-rc6 to support overlayfs.
 
 Usage:
 
 # Install arvados/migrate-docker19 image: @docker pull arvados/migrate-docker19:1.0@. If you're unable to do this, you can run @arvados/docker/migrate-docker19/build.sh@ to create @arvados/migrate-docker19@ Docker image.
+# Make sure you have the right modules installed: @sudo modprobe overlayfs bridge br_netfilter nf_nat@
 # Set ARVADOS_API_HOST and ARVADOS_API_TOKEN to the cluster you want to migrate.
 # Your temporary directory should have the size of all layers of the biggest image in the cluster, this is hard to estimate, but you can start with five times that size. You can set up a different directory by using the @--tmp-dir@ switch. Make sure that the user running the docker daemon has permissions to write in that directory.
 # Run @arv-migrate-docker19 --dry-run@ from the Arvados Python SDK on the host (not in a container). This will print out some information useful for the migration.