Looks like Linode may be having an outage in their Texas datacenter, which is affecting the us4 node and a few dedicated nodes (and is also affecting my ability to check the status of those nodes). This is a really recent development as it has not appeared on the 
Linode status page yet. If the issue continues for more than a few minutes it should appear there.
I'll keep this post updated on the status.
Update: Linode has updated their status page and has marked a 'major outage' on both their management api and the Texas datacenter.
Update: Nodes in the Texas region including us4 appear to be online again.