diff --git a/docs/concepts/containers/container-environment-variables.md b/docs/concepts/containers/container-environment-variables.md
index 87ebd51bed..07f2e2caba 100644
--- a/docs/concepts/containers/container-environment-variables.md
+++ b/docs/concepts/containers/container-environment-variables.md
@@ -38,7 +38,7 @@ as are any environment variables specified statically in the Docker image.
 
 ### Cluster information
 
-A list of all services that were running when a Container was created are available to that Container as environment variables.
+A list of all services that were running when a Container was created is available to that Container as environment variables.
 Those environment variables match the syntax of Docker links.
 
 For a service named *foo* that maps to a container port named *bar*,