As a priest in heaven Jesus administers a better covenant, not bound by earthly conventions. He administrates it in a tabernacle built by God himself!
The most amazing part of this chapter is Hebrews 8:6. The new covenant is built on better promises. They are better because they are unilateral. The quote from Jeremiah 31:31-34 explains what he means. Sins can be forgiven, not just covered. Our performance is not a basis for this covenant. God's performance is the only thing at stake!