No -- by your definition.
But when Russia is shooting down planes from its territory, and training and supplying and arming the rebels, and when commanders in the field are Russian GRU, then it's an undeclared war with Russia.
“But when Russia is shooting down planes from its territory”
Again, your proof please?
Just as in Crimea, where Russia was denying any part, while soldiers in Russian uniforms and vehicles were organizing and directing attacks.